A new method with in-line F-T computer-generated holograms is proposed to synthesize the coded gratings for the coded grating F-T diffraction interferometry, so that it becomes effective in practice that various forms of interference can be achieved by using different masks. As a result, any abnormal forms of interference can be easily obtained. The required F-T spectrum commonly consists of geometric patterns, thus, another new idea is proposed that the corresponding object function can be expressed by pure phase variations in geometric consideration. Therefore, the CGHs used for coded gratings are really computer-generated interferograms that can be more easily prepared, and the calculation for 2D Fourier transformation can be totally economized.
The Fabry-Perot resonator used for loss measurements of optical waveguides has been systematically analyzed. It has been found for the first time that this method can also be used for the loss measurements of glass waveguides prepared by the ion exchange method.
This paper describes the photo luminescence detection apparatus, which consists of a pulsed CuBr laser with low duty cycle and a boxcar averager. It features high sensitivity and good repeatability. The photoluminesoent spectra of a liquid-phase epitaxial GaP:N wafer have been measured in the temperature range 80-300K and for different thicknesses. Based on the spectra, the green-light emitting mechanism is analysed. It is found that the spectra are mainly composed of A-O and NN1 peaks in the range of 80~160 K,while the A peak and its phonon-associated peaks dominate over the spectral in the range of 160~300 K. The NN1 peaks are very prominent in the spectra of different epitaxial layers. Analysis of NN3 peaks could help prepare high efficient green-light-emitting GaP:N materials.
The refractive index profile of a gradieEt index sphere can be measured rapidly, automatically and condestructively by a large aperture shearing harmonic interferometer. The apparatus, principle and technique of measurement are described and the data treatment and results are discussed. Computer simulation and experiments show that the curved ray analysis gives better accuracy than the straight ray analysis for large Δn in transverseinterferometry.
The continuous and accurate tuning of a semiconductor laser with an external dispersive cavity over the whole frequency range determined by oscillating conditions can be achieved by varying the temporature and injection current of the laser diode and the length of the external cavity. This article reports the principles and some experimental results.
This paper describes an n+-p InSb/Hg1-xCdxTe heterojunction prepared by using liquid-phase epitaxial method. The growing system used consists of a horizontal slider boat in the open-tube filled with H2. Growth temperature is between 300-400℃ and cooling rate is slower than 8℃/min. The grown film has a mirror-like surface with a thickness of l5-25μm. EDAX-SEM analysis shows that the interface between layer and substrate is straight and the compositional transition is very sharp.
Starting from the mechanism of intensity-dependent absorption found experimentally in BSO crystals, we derived-the nonlinear coupled-wave equations, taking the interaction between self-diffraction and recording of grating into account. They are used for describing the two-wave interaction in BSO crystals. With the model for dynamic interaction, a method of numerical solution was put forwwrd. The calculated results accounted successfully for the disagresment between previous theories and experiments. Under various physical conditions, the characteristics of the two-wave inter action vrere calculated. They were born out by experiments.
In this paper, the integral equation of two-dimensional diifraotion i9 introduced. The intensity distribution of the two-dimensional diffraction of a corner pattern through a projeotive optical system is computed numerically. A simplified transmission model of the corner pattern is suggested. The calculated value of the round radius of the corner pattern through the projective optical system is in agreement with the measured value.
The design principle of the Wollaston prism with rotated optical axis is presented. By cascading the above mentioned prisms with the conventional Wollaston prisms in an alternate way the multiple imaging operation can be carried out. The experiments are in good agreement with theory.
In this paper, the ray matrix in lenslike media is derived from the simple refraction law. By introducing the equivalent index of refraction, the self-focusing phenomenon of Gaussian beam and Super-Gaussian beam are treated more intuitively. The results obtained are consistent with those derived from using other methods.
The sensibility of the PZT scanning F-P interferometer to the temperature is a serious problem for the stability of the optical system. Methods to solve this problem are suggested in this paper, so that the system can measure weak optical spectra.
We have measured the spectrum of Coherent Anti-Stokes Raman Spectroscopy (CARS) of N2 in a C2H2/air flame and computed its theoretical spectrum. Based on the 30mparison between theoretical and experimental spectra, wo have determined the tempareture of the flame. It is in agreement with what we got by using the method of laser-exoited fluorescence of OH in the same flame.
This paper deals with a new method for processing of lateral shear interferograms. An optimal reference sphere is introduced in the fitting process so that the testing result becomes more reliable and rational. In this way, the shear interferogram of a mirror is processed with results conforming with the actual situation.
Systematic measurements of a go out radiation signal from our Raman free-electron laser indicated a good agreement between experimental data and theoretical calculations. As a results, the optimal parametric region for the laser operation can be determined, making it possible to furthor improve the performance of the laser.
We have detected the two-photon absorption signals of Ba in a heat-pipe cell using a thermoelectronic diode. The relations between signal characteristics and pressure, temperature, bias voltage, position of interaction zone were studied both experimentally and theoretically.