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Step 3, Phase measurement: First make sure that auto exposure mode is switched off (Fig. 7), then set the spectral range to second harmonic (Fig. 8 upper). Then tune the crystal to the correct wavelength by checking the tune to center of gravity box as an alternative (Fig. 8 lower). You can manually enter the center wavelength and press the tune button. Be sure to reset the exposure time if needed. If you need to further optimize the signal you can adjust the focus mirror by using the hex key provided with your LX spider. Then, activate auto-exposure mode and set the spectral range to fundamental. Press the safe calibration button and when you’re asked to replace the spectrum choose “no”.
| Figure 7. auto-exposure off | Figure 8. spectral range to second harmonic; checking the tune to the center of gravity (COG)box | Figure 9. activate auto-exposure set the spectral range to fundamental Press the safe calibration button, choose “no” to replace the spectrum |
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Step 4, Result: Then return the spectral range to the second harmonic. LX Spider will immediately show you the pulse in the spectral domain. The previously saved pulse spectrum will appear as a white curve and the current reconstruction of the spectral phase will appear as a blue curve. You can evaluate the chirp of the pulse from the curvature of the phase. If you’d like to see the actual temporal pulse shape click the time domain button. A second graph will open the display. The pulse shape at the Fourier limit in green and the actual pulse shape as a white curve.
| Figure 10. return the spectral range to second harmonic | Figure 11. The previously saved pulse spectrum ( white curve) and the reconstructed spectral phase (blue curve) | Figure 12 click the time domain button.The pulse shape at the Fourier limit in green and the actual pulse shape as a white curve. |
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Results contains contain the following information:
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