In this research, we propose a method that utilizes machine learning to maintain the parallelism of resonant cavity in Fabry–Perot interferometer designed specifically for glass substrates. Based on optical principle and theory, establish proportional relationship between interference fringes inclination angle mirrors. This enables an accurate determination using supervised learning, classifica...

The method of random sampling was introduced for the first time in the nutation nuclear quadrupole resonance (NQR) spectroscopy where the nutation spectra show characteristic singularities in the form of shoulders. The analytic formulae for complex two-dimensional (2-D) nutation NQR spectra (I = 3/2) were obtained and the condition for resolving the spectral singularities for small values of an...

We present theory, design, and preliminary experimental studies for a compact wavefront sensor based on lateral shearing interferometry using a binary phase grating, image sensor, and Fourier-based processing. The integrated system places a diffractive element directly onto an image sensor to generate interference fringes within overlapping diffraction orders. The shearing ratio and the interfe...

Single axial-mode operation of the pulsed far-infrared p-Ge laser with an intracavity Fabry–Perot type frequency selector has been observed by means of Fourier-transform spectroscopy. A spectral resolution better than 1 GHz has been achieved on an ordinary continuous-scan spectrometer using the event-locked technique for pulsed emission sources. A laser active-cavity finesse of at least unity h...

In phase-shifting interferometry with unknown phase shifts, a normalization and orthogonalization phase-shifting algorithm (NOPSA) is proposed to achieve phase retrieval. The background of interferogram is eliminated through using the orthogonality of complex sinusoidal function; and the influence of phase shifts deviation on accuracy of phase retrieval is avoided through both normalization and...

We experimentally created a femtosecond optical vortex using a pair of computer-synthesized holographic gratings arranged in a 2f - 2f optical setup. We present measurements showing that the resulting donut mode is free of spatial chirp, and support this finding with an analysis of the optical wave propagation through our system based on the Kirchhoff-Fresnel diffraction integral. An interferog...

Spatial heterodyne spectroscopy (SHS) is a Fourier-transform spectroscopic technique that simultaneously records all path differences using a detector array. Compared to conventional Fourier-transform spectroscopy that measures interferogram samples sequentially in the time domain, SHS is insensitive to a changing scene; however, the effects caused by differences in the detector elements and/or...

The Institut Cartogràfic de Catalunya (ICC) has developed an automatic advanced DInSAR processor (DISICC) for subsidence monitoring of large areas using data acquired by ERS-1/2, ENVISAT, and the future ALOS, TerraSAR-X and Radarsat 2 satellites. This processor performs the co-registration, interferogram generation, filtering, topographic cancellation, linear deformation model adjustment and no...

Bistatic SAR systems are an emerging research field, in which context the Universitat Politecnica de Catalunya is developing a ground based bistatic system using ESA’s ENVISAT and ERS-2 as transmitters. The spatial resolution of this configuration is similar to that of their monostatic counterpart, although foreshortening effects have a lesser impact. The formulation of the interferometric phas...

A new bunch-length measuring method has been developed to measure the subpicosecond electron pulses generated at the Stanford SUNSHINE facility. This method utilizes a far-infrared Michelson interferometer to measure coherent transition radiation emitted at wavelengths longer than or equal to the bunch length via optical autocorrelation. To analyze the measurement, a simple and systematic way h...