Abstract: A simple on-site transmittance measurement setup that is easy to move and install is proposed in this study. It is especially suitable for those cases when laboratory instruments are not applicable. Ordinarily, witness samples are measured since the uniformity is good enough inside the thin film coator and the size of the sample is proper for the facilities to measure. When the spot size of the measuring instrument is too large for the filter or the size of the test sample is too large to fit into the instrument. The proposed setup is shown to work well for this measurement. An application for this setup is also presented. The test target was a stripe filter, which has five band-pass thin films and nominal dimensions of 120 x 3.6 mm each film. Distance between neighboring films is 3.85 mm. The width of each film is so narrow and the size the stripe filter is large such that the traditional method for spectral transmittance is not applicable. The proposed measurement setup consists of a light source, integration sphere and spectrophotometer. The setup was installed inside a dark room. It shows that the setup can provide as accurate results as those data measured by an accreditated instrument. The difference between the present setup and accreditated instrument was found within 7% for high radiance. When the radiance of the incident light is low the accuracy decreases, which can be compensated by stronger light source. In addition, since the measurement spot size is estimated as 1.5 x 2.1 mm it can provide local transmittance data along the stripe thin film rather than a single data represented by the witness sample.
Abstract: We propose a new approach for determining the distribution of full-field refractive index based on the angle deviation method (ADM) with a surface plasmon resonance (SPR) sensor in phase detection. The inhomogeneous distribution of refractive index causes the variant deviation angles in the test light. SPR sensor is a sensitive angular sensor especially for phase detection. For the full–field phase measurement, we should use the four-step phase shift interferometry (PSI) to measure the phase shift profile of the test light after reflected from the SPR sensor. Thus the phase shift is caused by the variation of the refractive index. The approach can plot the full-field refractive index distribution in a short time and its resolution can be better than 2.2×10-8 (RIU).
Abstract: Self-mixing interference (SMI) was used to measure the displacement with a resolution of λ/2 by counting the interference signal peaks. In order to increase the measurement accuracy beyond λ/2, sinusoidal wavelength modulation (SWM) technique is introduced in SMI in this paper. Wavelength modulation of the laser beam is obtained by sinusoidal modulating the injection current of the laser diode. Fourier analysis method is proposed to demodulate the phase. Experimentally, the micro-movements of a high precision commercial PZT have been reconstructed, which can obtain a displacement measurement resolution of a few nanometers. It provides a potential displacement sensor with high accuracy and quite compact configuration.
Abstract: We demonstrated a scanning radially-polarized surface plasmon microscopy (SSPM) with submicron lateral resolution and high refractive index sensitivity. According to the captured images, SSPM could be used to verify the quality of deposited Au film and Au structure on surface plasmon sensing chip. The defect on the SPR chip, which disturbed the plasmonic wave around the focal point, could be easily detected by our system. Moreover, the application of SSPM in imaging lipid array was showed in this article. The 1, 2-Dioleoyl-sn-glycero-3-phosphocholine (DOPC) array was made by dip-pen nanolithography. The results indicated that SSPM system could be used in comparing the thickness of DOPC array. Because of the high sensitivity and high spatial resolution of the system, we expected the SSPM to be used in measuring the properties of nanogold array structures and apply to digital-array biosensors in nanoscale.
Abstract: In this paper, a non-mechanical axial zoom scanning method based on a phase only liquid crystal spatial light modulator is proposed. This novel method is to overcome the measurement error caused by moving mechanical parts in the axial mechanical scanning methods in the confocal microscopy system. The modulation on the incident wave front is completed by a spatial light modulator, which provides this scanning method some outstanding advantages including the flexibility of control and the absence of moving mechanical parts, especially suitable for the fixed sample imaging occasions. By simulating the multiple Fresnel lens with LCSLM to generate controllable multi-focal points and thus realizing this method of axial multi-focus scanning to enhance the axial scanning efficiency and the range. Simulations and experiments on the axial scanning features of the axial multi-focus zoom scanning method are carried out. Results of simulations and experiments indicate that non-mechanical axial zoom scanning can be realized with the use of a spatial light modulator in the confocal microscopy system.
Abstract: As is well known, the phase-shifting interferometry techniques allow to reach longitudinal resolution to ~ 0.1 nm, but the value of lateral resolution remains at the level of ~ 1 mm. For providing of high lateral resolution of linear measurements in the interference microscope profilometer it was proposed to use a position detection sensor of sharp edge. Principle of sensor’s measurement is based on registration of laser spot intensity scattered by the measurement sample surface under displacement of sample in the lateral direction. The paper shows the prototype scheme of measurement system containing the Linnik interferometer used for surface nanorelief measurement and a position detection module of sharp edge. Measurement process and experimental results are presented. The combining of measurement results performed by the Linnik interferometer and a position detection sensor of sharp edge can allow us to precisely (better then diffraction limit) define the position of sharp edge on the reconstructed surface nanorelief.
Abstract: Modern industry and science take novel 3D optical measuring systems and laser technologies with high resolution. For solving their actual problems we have developed the family of the optical measuring systems and technologies. Peculiarities of 3D image formation under partially coherent illumination using constructive calculation method are given. The optical methods and system for 3D dimensional inspection of ceramic parts are presented. The performances of 3D super resolution optical low-coherent micro-/nanoprofilometer are given. Using atomic perfectly-smooth mirror as a reference object, the breakthrough in-depth measurement with 20 picometers was achieved. The newest results in the field of laser technologies for high-precision synthesis of microstructures by updated image generator using the semiconductor laser are presented. The measuring systems and the laser image generator have been tested by the customers and are used in different branches of industry and science.
Abstract: The self-mixing interference (SMI) effect with multiway feedback is analyzed in this paper. The basic theory of SMI with multiway feedback external cavity (MFEC) can be derived from the theory of interference as well as the theory of laser self-mixing interference (LSMI). Based on the external cavity structure with MFEC, a SMI model with two feedback external cavity structure is proposed. The expressions of the phase and output power in the MFEC are deduced and some simulation analyses are made. It is found that the output signal of the SMI system with two external cavity is sinusoidal or sawtooth waves, which is similar to the signal of SMI with a low frequency sinusoidal phase modulation. The density of interference signal fringes is uneven in one period and the shape of the interference wave is determined by the intensity of the external feedback. Furthermore, a SMI with two feedback external cavity experiment system is considered, and the experiment verifies the simulations.
Abstract: Integrated-Circuit (IC) test probes have been designed variously and manufactured flexibly cause of diverse IC packaged forms. To successfully test the functions of the packaged IC, the packaged industry should carefully select a suitable probe type based on the size or pitch of the ball and the lead of the packaged IC. One plunger of the probe is used to be connected with the packaged IC; the other plunger is connected to the testing devices. A probe basically is composite of a barrel and two plungers whose head might be the crown or the pierced type. The main diameter of the probe’s barrel varies from 0.2 millimeter to 0.6 millimeter; the total length of the probe could be from 1 millimeter to 7 millimeter. The probes ought to be detected before implanting them into the housing socket. However, the presenting probe measure method, eye checking by human beings, cannot fulfill the diverse types of probes because the size of IC becomes more delicate and smaller. This paper aims to develop an intelligent system that can detect and recognize more than ten items of a probe. The experimental results demonstrate that the proposed system can effectively measure the different probes.