Abstract: A method of performing coherent anti-stokes Raman spectroscopy (CARS) includes generating first and second optical pulse trains having different and adjustable repetition rates. One of the pulse trains is directed in a CW direction and the other in a CCW direction. A frequency shift and a first linear chirp is applied to optical pulses in the first optical pulse train. A second linear chirp is applied to optical pulses in the second optical pulse train. The first and second linear chirps having a common chirp rate. One of the chirped optical pulse trains is used as a pump beam and the other is used as a Stokes beam. The first and second chirped optical pulse trains are combined to define a combined beam. The combined beam is provided to a CARS spectroscopic system for exciting a resonant mode in a sample and generating a CARS signal.

Abstract: A method of interrogating an absorbing sample includes using a mode-locked laser mode-locked in both a clock-wise (CW) and a counter-clock wise (CCW) direction to generate first and second optical pulses having different repetition rates. One of the first and second optical pulses is directed in a CW direction and the other of the first and second optical pulses is directed in the CCW direction. The first optical pulses are transmitted through the absorbing sample to probe the absorbing sample while the second optical pulses are transmitted through the absorbing sample to act as a local oscillator. An interference pattern produced by interference between the first and second optical pulses is detected after traversing the absorbing sample.

Abstract: A method of interrogating an absorbing sample includes using a mode-locked laser mode-locked in both a clock-wise (CW) and a counter-clock wise (CCW) direction to generate first and second optical pulses having different repetition rates. One of the first and second optical pulses is directed in a CW direction and the other of the first and second optical pulses is directed in the CCW direction. The first optical pulses are transmitted through the absorbing sample to probe the absorbing sample while the second optical pulses are transmitted through the absorbing sample to act as a local oscillator. An interference pattern produced by interference between the first and second optical pulses is detected after traversing the absorbing sample.

Abstract: Probe beams are scanned with respect to waveguide substrates to generate optical harmonics. Detection of the optical harmonic radiation is used to image waveguide cores, claddings, or other structures such as electrodes. The detected optical radiation can also be used to provide estimates of linear electrooptic coefficients, or ratios of linear electrooptic coefficients. In some cases, the poling of polymer waveguide structures is monitored during fabrication based on a second harmonic of the probe beam. In some examples, third harmonic generation is used for imaging of conductive layers.

Abstract: Probe beams are scanned with respect to waveguide substrates to generate optical harmonics. Detection of the optical harmonic radiation is used to image waveguide cores, claddings, or other structures such as electrodes. The detected optical radiation can also be used to provide estimates of linear electrooptic coefficients, or ratios of linear electrooptic coefficients. In some cases, the poling of polymer waveguide structures is monitored during fabrication based on a second harmonic of the probe beam. In some examples, third harmonic generation is used for imaging of conductive layers.