https://optics.eee.nottingham.ac.uk/w/index.php?title=Ultrafast&feed=atom&action=historyUltrafast - Revision history2024-03-29T13:40:50ZRevision history for this page on the wikiMediaWiki 1.27.1https://optics.eee.nottingham.ac.uk/w/index.php?title=Ultrafast&diff=368&oldid=prevTeti at 18:29, 9 October 20082008-10-09T18:29:07Z<p></p>
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<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>A traditional detector arrangement is to focus the returning probe light onto a photodiode, the output of which goes to a lock-in amplifier, whose reference is the drive signal for the modulator. This yields a very sensitive detection system capable of measuring modulation depths in the range of 1 part in 10^6-10^7. Due to the slow speed of the mechanical delay line and the point measurement system, experiments can take a long time to perform making imaging applications impractical. We have developed custom made detectors that increase the data acquisition speed by more than an order of magnitude. We have achieved this by parallelising the detection by building a custom linear array detector which has very large light capturing ability. This combined with a suitable algorithm can replace the traditional photodiode/lock-in amplifier combination and provide a similar signal to noise ratio. The speed increases we have achieved have allowed us capture both 1D scans and more recently 2D images. Work progresses to improve the detectors and our system still further.  </div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>A traditional detector arrangement is to focus the returning probe light onto a photodiode, the output of which goes to a lock-in amplifier, whose reference is the drive signal for the modulator. This yields a very sensitive detection system capable of measuring modulation depths in the range of 1 part in 10^6-10^7. Due to the slow speed of the mechanical delay line and the point measurement system, experiments can take a long time to perform making imaging applications impractical. We have developed custom made detectors that increase the data acquisition speed by more than an order of magnitude. We have achieved this by parallelising the detection by building a custom linear array detector which has very large light capturing ability. This combined with a suitable algorithm can replace the traditional photodiode/lock-in amplifier combination and provide a similar signal to noise ratio. The speed increases we have achieved have allowed us capture both 1D scans and more recently 2D images. Work progresses to improve the detectors and our system still further.  </div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>This project has involved many people to date; Richard Smith has built up the main optical system and code to drive the experiment, with help and advice from Steve Sharples. Some of the samples that have been measured were prepared by Teti Stratoudaki. The custom detectors were designed and laid out primarily by Mark Pitter, Roger Light and Nick Johnston. The direction and drive of the project has been managed by Mike Somekh who brought us all together for this very successful project.</div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>This project has involved many people to date; Richard Smith has built up the main optical system and code to drive the experiment, with help and advice from Steve Sharples. Some of the samples that have been measured were prepared by <ins class="diffchange diffchange-inline">[[</ins>Teti Stratoudaki<ins class="diffchange diffchange-inline">]]</ins>. The custom detectors were designed and laid out primarily by Mark Pitter, Roger Light and Nick Johnston. The direction and drive of the project has been managed by Mike Somekh who brought us all together for this very successful project.</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>'''Conferences & Publications'''</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>'''Conferences & Publications'''</div></td></tr>
</table>Tetihttps://optics.eee.nottingham.ac.uk/w/index.php?title=Ultrafast&diff=340&oldid=prevRichard Smith at 08:46, 6 October 20082008-10-06T08:46:24Z<p></p>
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<td colspan='2' style="background-color: white; color:black; text-align: center;">Revision as of 08:46, 6 October 2008</td>
</tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l3" >Line 3:</td>
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<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>The main aim of this project is to dramatically increase the speed of picosecond ultrasonic experiments. Pico second ultrasonics is a well established laser ultrasound technique that is used for material characterisation.  </div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>The main aim of this project is to dramatically increase the speed of picosecond ultrasonic experiments. Pico second ultrasonics is a well established laser ultrasound technique that is used for material characterisation.  </div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>The experiments are based around the pump <del class="diffchange diffchange-inline">robe </del>technique where a pump laser pulse generates the acoustic waves and a time delayed probe pulse <del class="diffchange diffchange-inline">measured </del>the interaction of the sound wave with the sample. The time delay is controlled by scanning a large (and typically slow) mechanical stage. Due to the high frequency waves generated (in the low to hundreds of GHz) the pump beam is modulated at a lower intermediate frequency so that low frequency electronics can be used to capture the signals.  </div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>The experiments are based around the pump<ins class="diffchange diffchange-inline">-probe </ins>technique where a pump laser pulse generates the acoustic waves and a time delayed probe pulse <ins class="diffchange diffchange-inline">measures </ins>the interaction of the sound wave with the sample. The time delay is controlled by scanning a large (and typically slow) mechanical stage. Due to the high frequency waves generated (in the low to hundreds of GHz) the pump beam is modulated at a lower intermediate frequency so that low frequency electronics can be used to capture the signals.  </div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><del class="diffchange diffchange-inline">Traditional </del>detector arrangement is to focus the returning probe light onto a photodiode, the output of which goes to a lock in amplifier whose reference is the drive signal for the modulator. This yields a very sensitive detection system capable of measuring modulation depths in the range of 1 part in 10^6-10^7. Due to the slow speed of the mechanical delay line and the point measurement system <del class="diffchange diffchange-inline">the </del>experiments can take a long time to perform making imaging applications impractical. We have developed custom made detectors that increase the data acquisition speed by more than an order of magnitude. We have achieved this by parallelising the detection by building a custom linear array detector which has very large light capturing ability. This combined with a suitable algorithm can replace the traditional photodiode/lock-in amplifier combination and provide a similar signal to noise ratio. The speed increases we have achieved have allowed us capture both 1D scans and more recently 2D images. Work progresses to improve the detectors and our system still further.  </div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">A traditional </ins>detector arrangement is to focus the returning probe light onto a photodiode, the output of which goes to a lock<ins class="diffchange diffchange-inline">-</ins>in amplifier<ins class="diffchange diffchange-inline">, </ins>whose reference is the drive signal for the modulator. This yields a very sensitive detection system capable of measuring modulation depths in the range of 1 part in 10^6-10^7. Due to the slow speed of the mechanical delay line and the point measurement system<ins class="diffchange diffchange-inline">, </ins>experiments can take a long time to perform making imaging applications impractical. We have developed custom made detectors that increase the data acquisition speed by more than an order of magnitude. We have achieved this by parallelising the detection by building a custom linear array detector which has very large light capturing ability. This combined with a suitable algorithm can replace the traditional photodiode/lock-in amplifier combination and provide a similar signal to noise ratio. The speed increases we have achieved have allowed us capture both 1D scans and more recently 2D images. Work progresses to improve the detectors and our system still further.  </div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>This project has involved many people to date; Richard Smith has built up the main optical system and code to drive the experiment, with help and advice from Steve Sharples. Some of the samples that have been measured were prepared by Teti Stratoudaki. The custom detectors were designed and laid out primarily by Mark Pitter, Roger Light and Nick Johnston. The direction and drive of the project has been managed by Mike Somekh who brought us all together for this very successful project.</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>This project has involved many people to date; Richard Smith has built up the main optical system and code to drive the experiment, with help and advice from Steve Sharples. Some of the samples that have been measured were prepared by Teti Stratoudaki. The custom detectors were designed and laid out primarily by Mark Pitter, Roger Light and Nick Johnston. The direction and drive of the project has been managed by Mike Somekh who brought us all together for this very successful project.</div></td></tr>
</table>Richard Smithhttps://optics.eee.nottingham.ac.uk/w/index.php?title=Ultrafast&diff=339&oldid=prevRichard Smith at 13:22, 26 September 20082008-09-26T13:22:59Z<p></p>
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<td colspan='2' style="background-color: white; color:black; text-align: center;">Revision as of 13:22, 26 September 2008</td>
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<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>The main aim of this project is to dramatically increase the speed of picosecond ultrasonic experiments. Pico second ultrasonics is a well established laser ultrasound technique that is used for material characterisation.  </div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>The main aim of this project is to dramatically increase the speed of picosecond ultrasonic experiments. Pico second ultrasonics is a well established laser ultrasound technique that is used for material characterisation.  </div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>The experiments are based around the pump robe technique where a pump laser pulse generates the acoustic waves and a time delayed probe pulse measured the interaction of the sound wave with the sample. The <del class="diffchange diffchange-inline">d=</del>time delay is controlled by scanning a large (and typically slow) mechanical stage. Due to the high frequency waves generated (in the low to hundreds of GHz) the pump beam is modulated at a lower intermediate frequency so that low frequency electronics can be used to capture the signals.  </div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>The experiments are based around the pump robe technique where a pump laser pulse generates the acoustic waves and a time delayed probe pulse measured the interaction of the sound wave with the sample. The time delay is controlled by scanning a large (and typically slow) mechanical stage. Due to the high frequency waves generated (in the low to hundreds of GHz) the pump beam is modulated at a lower intermediate frequency so that low frequency electronics can be used to capture the signals.  </div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>Traditional detector arrangement is to focus the returning probe light onto a photodiode, the output of which goes to a lock in amplifier whose reference is the drive signal for the modulator. This yields a very sensitive detection system capable of measuring modulation depths in the range of 1 part in <del class="diffchange diffchange-inline">106</del>-<del class="diffchange diffchange-inline">107</del>. Due to the slow speed of the mechanical delay line and the point measurement system the experiments can take a long time to perform making imaging applications impractical. We have developed custom made detectors that increase the data acquisition speed by more than an order of magnitude. We have achieved this by parallelising the detection by building a custom linear array detector which has very large light capturing ability. This combined with a suitable algorithm can replace the traditional photodiode/lock-in amplifier combination and provide a similar signal to noise ratio. The speed increases we have achieved have allowed us capture both 1D scans and more recently 2D images. Work progresses to improve the detectors and our system still further.  </div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>Traditional detector arrangement is to focus the returning probe light onto a photodiode, the output of which goes to a lock in amplifier whose reference is the drive signal for the modulator. This yields a very sensitive detection system capable of measuring modulation depths in the range of 1 part in <ins class="diffchange diffchange-inline">10^6</ins>-<ins class="diffchange diffchange-inline">10^7</ins>. Due to the slow speed of the mechanical delay line and the point measurement system the experiments can take a long time to perform making imaging applications impractical. We have developed custom made detectors that increase the data acquisition speed by more than an order of magnitude. We have achieved this by parallelising the detection by building a custom linear array detector which has very large light capturing ability. This combined with a suitable algorithm can replace the traditional photodiode/lock-in amplifier combination and provide a similar signal to noise ratio. The speed increases we have achieved have allowed us capture both 1D scans and more recently 2D images. Work progresses to improve the detectors and our system still further.  </div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>This project has involved many people to date; Richard Smith has built up the main optical system and code to drive the experiment, with help and advice from Steve Sharples. Some of the samples that have been measured were prepared by Teti Stratoudaki. The custom detectors were designed and laid out primarily by Mark Pitter, Roger Light and Nick Johnston. The direction and drive of the project has been managed by Mike Somekh who brought us all together for this very successful project.</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>This project has involved many people to date; Richard Smith has built up the main optical system and code to drive the experiment, with help and advice from Steve Sharples. Some of the samples that have been measured were prepared by Teti Stratoudaki. The custom detectors were designed and laid out primarily by Mark Pitter, Roger Light and Nick Johnston. The direction and drive of the project has been managed by Mike Somekh who brought us all together for this very successful project.</div></td></tr>
</table>Richard Smithhttps://optics.eee.nottingham.ac.uk/w/index.php?title=Ultrafast&diff=314&oldid=prevRichard Smith at 09:20, 18 September 20082008-09-18T09:20:26Z<p></p>
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<td colspan='2' style="background-color: white; color:black; text-align: center;">Revision as of 09:20, 18 September 2008</td>
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<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>'''Conferences & Publications'''</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>'''Conferences & Publications'''</div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">Parallel detection of low modulation depth signals: application to picosecond ultrasonics, R J Smith, M G Somekh, S D Sharples, M C Pitter, I Harrison and C Rossignol , Meas. Sci. Technol. 19 (2008) 055301 (8pp)</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">Parallel Ultrafast ultrasonics, R Smith, M Somekh S Sharples, M Pitter, R Light, N Johnston, Rank prize funds - mini symposia on optical aspects of NDT, 19-22nd May 2008 Grasmere cumbria </ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">Parallel Detection for picosecond ultrasonics, RJSmith MG somekh, S Sharples, M Pitter, R light, N Johnston, Acoustics ’08,Paris, June 2008, article 003508</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">Parallel detection in picosecond ultrasonics with both commercial and custom array detection,R Smith, M Somekh, S Sharples, M Pitter, R Light, N Johnston, 1st Symposium of Laser ultrasonics, Montreal Canada, July 2008.</ins></div></td></tr>
</table>Richard Smithhttps://optics.eee.nottingham.ac.uk/w/index.php?title=Ultrafast&diff=313&oldid=prevRichard Smith at 09:19, 18 September 20082008-09-18T09:19:03Z<p></p>
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<td colspan='2' style="background-color: white; color:black; text-align: center;">Revision as of 09:19, 18 September 2008</td>
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<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>'''Exotic ultrasonics for the real world'''</div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>'''Exotic ultrasonics for the real world <ins class="diffchange diffchange-inline">(Ultrafast project)</ins>'''</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><del class="diffchange diffchange-inline">description </del>to <del class="diffchange diffchange-inline">follow</del></div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">The main aim of this project is </ins>to <ins class="diffchange diffchange-inline">dramatically increase the speed of picosecond ultrasonic experiments. Pico second ultrasonics is a well established laser ultrasound technique that is used for material characterisation. </ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div> </div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">The experiments are based around the pump robe technique where a pump laser pulse generates the acoustic waves and a time delayed probe pulse measured the interaction of the sound wave with the sample. The d=time delay is controlled by scanning a large (and typically slow) mechanical stage. Due to the high frequency waves generated (in the low to hundreds of GHz) the pump beam is modulated at a lower intermediate frequency so that low frequency electronics can be used to capture the signals. </ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div> </div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">Traditional detector arrangement is to focus the returning probe light onto a photodiode, the output of which goes to a lock in amplifier whose reference is the drive signal for the modulator. This yields a very sensitive detection system capable of measuring modulation depths in the range of 1 part in 106-107. Due to the slow speed of the mechanical delay line and the point measurement system the experiments can take a long time to perform making imaging applications impractical. We have developed custom made detectors that increase the data acquisition speed by more than an order of magnitude. We have achieved this by parallelising the detection by building a custom linear array detector which has very large light capturing ability. This combined with a suitable algorithm can replace the traditional photodiode/lock-in amplifier combination and provide a similar signal to noise ratio. The speed increases we have achieved have allowed us capture both 1D scans and more recently 2D images. Work progresses to improve the detectors and our system still further. </ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div> </div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">This project has involved many people to date; Richard Smith has built up the main optical system and code to drive the experiment, with help and advice from Steve Sharples. Some of the samples that have been measured were prepared by Teti Stratoudaki. The custom detectors were designed and laid out primarily by Mark Pitter, Roger Light and Nick Johnston. The direction and drive of the project has been managed by Mike Somekh who brought us all together for this very successful project.</ins></div></td></tr>
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<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">'''Conferences & Publications'''</ins></div></td></tr>
</table>Richard Smithhttps://optics.eee.nottingham.ac.uk/w/index.php?title=Ultrafast&diff=305&oldid=prevRichard Smith: New page: '''Exotic ultrasonics for the real world''' description to follow2008-09-16T14:14:36Z<p>New page: '''Exotic ultrasonics for the real world''' description to follow</p>
<p><b>New page</b></p><div>'''Exotic ultrasonics for the real world'''<br />
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description to follow</div>Richard Smith