Spectral Phase Transfer Research Articles

Spectral phase transfer from near IR to deep UV by broadband phase-matched four-wave mixing in an argon-filled hollow core waveguide

We report on the implementation of a spectral phase transfer scheme from near IR to deep UV, in which the frequency conversion step is based on the broadband phase-matched four-wave mixing in a gas-filled hollow core waveguide. Micro joule level femtosecond pulses at 260 nm were generated by nonlinear mixing of a Ti:sapphire laser and its second-harmonic. The transfer of a π-step phase in a controllable manner was proposed and confirmed by a modulation observed in the generated deep UV femtosecond pulse spectrum due to an interference process. Numerical simulations confirmed our results.

Spectral phase transfer to ultrashort UV pulses through four-wave mixing

Transfer of spectral phase from near infrared ultrashort pulses to deep ultraviolet (UV) sub-30-fs pulses through four-wave mixing process is demonstrated. Micro joule UV pulses at 237 nm were generated by nonlinear mixing of second harmonic pulses of Ti:sapphire laser output and near infrared pulses from a noncollinear optical parametric amplifier. Chirp of the near infrared pulse was transferred to the UV pulse with the opposite sign. A positively chirped near infrared pulse was used for generating a negatively chirped UV pulse, which was compressed down to 25 fs by a magnesium fluoride window.

Spectral transfer function of the Fourier transform spectral imager

The spectral transfer function of the imaging spectrometer is defined on the basis of the linear system theorem. The spectral transfer functions including spectral modulation transfer functions and the spectral phase transfer functions of the temporally modulated Fourier transform spectral imager based on Michelson interferometer and those of the spatially modulated Fourier transform spectral imagers based on Sagnac interferometer,Fresnel interferometer, and Lloyd interferometer are deduced. These spectral transfer functions could be regarded as an objective criteria in the spectral domain of spectral imagers. Together with the well known optical transfer function, the performance of the imaging spectrometer could be described comprehensively.

Spectral phase transfer for indirect phase control of sub-20-fs deep UV pulses

We demonstrate the transfer of a shaped spectral phase in a pulse with a sub-20-fs pulse Fourier limit of a Ti:sapphire laser to that in a deep UV pulse at 256 nm in a sum- frequency-mixing process. The generated UV pulse maintains a sufficiently broad spectrum to form a sub-20-fs pulse due to broadband sum-frequency mixing with the group-delay-dispersion-matched scheme. The spectral phases of the deep UV pulse are measured with spectral phase interferometry for direct electric field reconstruction and compared with the phase applied to the Ti:sapphire laser pulse.

Enhanced linear and nonlinear optical phase response of AlGaAs microring resonators.

We have constructed and characterized several optical microring resonators with scale sizes of the order of 10 microm. These devices are intended to serve as building blocks for engineerable linear and nonlinear photonic media. Light is guided vertically by an epitaxially grown structure and transversely by deeply etched air-clad sidewalls. We report on the spectral phase transfer characteristics of such resonators. We also report the observation of a pi-rad Kerr nonlinear phase shift accumulated in a single compact ring resonator evidenced by all-optical switching between output ports of a resonator-enhanced Mach-Zehnder interferometer.