Optical Slits Research Articles

A microchip based Z-cell absorbance detector integrating micro-lenses and slits for portable liquid chromatography

A miniaturized microchip-based absorbance detector was developed for portable high-performance liquid chromatography (HPLC) to test glycated hemoglobin (HbA1c). The microchip integrating a Z-shaped cell, two collimating micro-lenses and two ink-filled optical slits is small in size (30 mm × 15 mm × 7 mm). The Z-shaped cell has a cross-sectional size of 500 μm × 500 μm and a physical optical path length of 2 mm. Two collimating micro-lenses were inserted in empty grooves on both sides of the cell, one micro-lens for collimating the initial light and the other for focusing the transmitted light. Optical slits on each end of the cell were used to block the stray light. Therefore, this detector indicated a low stray light level (0.011 %) and noise level (2.5 × 10−4 AU). This detector was applied for the commercial HPLC system to detect HbA1c level, and showed a low limit of detection (0.5 μg/mL) and excellent repeatability (≤ 2.03 %). The sensitivity was enhanced by 3.4 times when the optical path length was increased from 0.5 mm to 2 mm and the stray light was blocked by optical slits. The miniaturized microchip-based absorbance detector developed shows a great potential for application in portable and compact HPLC.

Wireless wavelength measurement system with temperature compensation using filter-free wavelength sensors

Abstract Portable wavelength detection systems have been developed for various environmental and biochemical applications. Conventional systems have some limitations as they are unable to adapt to changes in wavelength and rely on optical filters or slits to distinguish between different wavelengths. To address these limitations, a filter-free wavelength sensor system was proposed, utilizing the absorption coefficient of silicon to identify wavelengths. The proposed system comprises an analog circuit for measuring photocurrent from a filter-free wavelength sensor, integrated with a temperature sensor and microcontroller for signal processing. The proposed system can measure currents with a resolution of 1.2 pA within a 30 nA range, achieving a coefficient of determination of 0.999 for measured currents in relation to light intensity. The microcontroller features a temperature compensation algorithm, enabling wireless control and data transmission. Applying temperature compensation reduced the rate of errors in the data by 61%. By eliminating the need for optical components, a wireless measurement system was developed that can accurately identify wavelengths.

Beam-shaping device-free femtosecond laser plane-by-plane inscription of high-quality FBGs

Fiber Bragg gratings (FBGs) fabricated by femtosecond laser point-by-point inscription suffer from insertion loss (IL) and polarization-dependent loss (PDL) which degrade their performances in optical communication and sensing. To solve this problem, we propose a new method to realize plane-by-plane (Pl-b-Pl) inscription of high-quality fiber Bragg gratings by using high refractive index (RI) oil. The focal volume of the laser beam can be “stretched” due to the dispersive effect of the high RI oil along the transverse direction of the fiber. Compared to the reported femtosecond laser Pl-b-Pl grating inscription method, the high RI oil for Pl-b-Pl grating inscription is a simple and efficient method without additional beam-shaping devices (e.g., optical slits and spatial light modulators). Using the proposed method, a high-quality FBG can be inscribed, which has a high reflectivity of 98.1% (the Bragg resonance attenuation of 17.23 dB), and a low short-wavelength loss of 0.84 dB, and a low insertion loss of 0.23 dB. Most importantly, the PDL of the grating is only 0.12 dB.

Adjustable Optical Slit Based on the Phase Type Spatial Light Modulator

In this paper, we propose an adjustable optical slit based on a phase type spatial light modulator (SLM). The adjustable optical slit consists of two polarized beam splitters and one SLM. The SLM is used to modulate the phase of light. A phase grayscale with specific structure is produced, where the middle phase is 0 and the phase on both sides is π. By changing the width of the slit grayscale, we can adjust the width of the slit easily. Our experiment shows that one-dimensional (1-D) slit and 2-D mask can be realized and the slit width can be tuned accordingly. The results verify its feasibility. The adjustment accuracy of slit can reach several microns, and the slit can also be laterally translated. The proposed device can be used not only in optical system or holographic display to improve the quality of the image, but also in spectrometers to select the specific spectral feature.

Local deformation calibration for autostereoscopic 3D display.

Calibration is vital to autostereoscopic 3D displays. This paper proposes a local calibration method that copes with any type of deformation in the optical layer. The proposed method is based on visual pattern analysis. Given the observations, we manage to localize the optical slits by matching the observations to the input pattern. In a principled optimization framework, we find an efficient calibration algorithm. Experimental validation follows. The local calibration shows significant improvement in 3D visual quality over the global calibration method. This paper also finds a new intuitive insight on the calibration in terms of the light field theory.

Young-type interference in projectile-electron loss in energetic ion-molecule collisions

We propose an alternative and very promising scenario for studying the Young-type-interference phenomena in energetic ion-molecule collisions. In such a scenario, we focus on the energy spectra of electrons that are ionized from the bound states of fast moving projectiles. We argue that under certain conditions these (projectile) electrons interact mainly with the nuclei and inner-shell electrons of atoms forming the molecule. Due to their compact localization in space and distinct separation from each other, these molecular centers play a role similar to that of optical slits in light scattering leading to pronounced interference patterns in electron energy distributions.

Young-Type Interference in Projectile-Electron Loss in Energetic Ion-Molecule Collisions

Under certain conditions an electron bound in a fast projectile ion, colliding with a molecule, interacts mainly with the nuclei and inner shell electrons of atoms forming the molecule. Because of their compact localization in space and distinct separation from each other, these molecular centers play in such collisions a role similar to that of optical slits in light scattering leading to pronounced interference in the spectra of the electron emitted from the projectile.

Phase shifting grating-slit test with a cross slit

A general graphical convolution method for fringe analysis of testing methods that use a spatially incoherent light source is presented. Results are shown for the grating-slit test using optical narrow and cross slits. The convolution method shows that phase shifting grating-slit test can be done with the cross slit at the expense of a reduced fringe contrast ratio. A phase shifting measurement with a cross-slit modulator yields high measurement precision and validates our fringe contrast theory.

Imaging photomultiplier array with integrated amplifiers and high-speed USB interface

Multianode photomultiplier tube (PMT) arrays are finding application as convenient high-speed light sensitive devices for plasma imaging. This paper describes the development of a USB-based "plug-n-play" 16-channel PMT camera with 16 bits simultaneous acquisition of 16 signal channels at rates up to 2 MSs per channel. The preamplifiers and digital hardware are packaged in a compact housing which incorporates magnetic shielding, on-board generation of the high-voltage PMT bias, an optical filter mount and slits, and F-mount lens adaptor. Triggering, timing, and acquisition are handled by four field-programmable gate arrays (FPGAs) under instruction from a master FPGA controlled by a computer with a LABVIEW interface. We present technical design details and specifications and illustrate performance with high-speed images obtained on the H-1 heliac at the ANU.

Carrier mobility of organic thin films using lateral electrode structure with optical slits

The authors have studied the carrier mobilities of organic thin films using a time-of-flight (TOF) technique with lateral electrode structures and optical slits. For a triphenylamine derivative (TPD), which is a typical hole transport material, the obtained mobility was similar to the results of the conventional TOF measurement using a sandwiched structure with a thick film. Moreover, they have succeeded in evaluating the carrier mobility of an iridium complex [Ir(ppy)3], which is a phosphorescent material, and hole mobility on the order of 10−3cm2∕Vs was obtained. This technique, which has the merits of free alignment of excitation light and no need for the preparation of a thick sample, is effective for the evaluation of carrier mobilities in thin organic materials.

A large-volume high-pressure and high-temperature apparatus for in situ X-ray observation, ?SPEED-Mk.II?*1

SPEED-Mk.II, the second KAWAI-type high P–T apparatus for in situ X-ray observation that was installed at the bending magnet beam line at SPring-8, is described. The guide block system was designed so that the change of the relative dimension of the cubic compression space with press load can be minimized by repeated adjustments. The hydraulic system was designed so as to enable smooth compression and decompression. These precise controls should be advantageous for high-pressure generation, especially when sintered diamond (SD) anvils are used. An oscillation system was equipped for the first time in a large volume press, making it possible to obtain high-quality diffraction patterns even when the number of sample grains is limited. The use of the oscillation system also reduces errors in pressure determination that may be caused by insufficient averaging of diffraction angles over grains in a limited diffraction volume, because the oscillating grains should sweep through the 2θ range that is allowed by the finite widths of the optical slits.

A large-volume high-pressure and high-temperature apparatus for in situ X-ray observation, ‘ SPEED-Mk.II’

SPEED-Mk.II, the second KAWAI-type high P– T apparatus for in situ X-ray observation that was installed at the bending magnet beam line at SPring-8, is described. The guide block system was designed so that the change of the relative dimension of the cubic compression space with press load can be minimized by repeated adjustments. The hydraulic system was designed so as to enable smooth compression and decompression. These precise controls should be advantageous for high-pressure generation, especially when sintered diamond (SD) anvils are used. An oscillation system was equipped for the first time in a large volume press, making it possible to obtain high-quality diffraction patterns even when the number of sample grains is limited. The use of the oscillation system also reduces errors in pressure determination that may be caused by insufficient averaging of diffraction angles over grains in a limited diffraction volume, because the oscillating grains should sweep through the 2 θ range that is allowed by the finite widths of the optical slits.

Microfabricated CE Chips with Optical Slit

In order to improve detection sensitivity of UV absorption detection on a chip for capillary electrophoresis (CE), we have developped the microfabricated CE chips which have silicon shade at bonding interface. Although the CE chips are fabricated with a simple process, the Si shade is ideal structure as an optical slit. It was confirmed, using the CE chips, that the detection sensitivity of UV absorption detection was improves about ten times, and a DNA sample analysis with UV absorption detection was perfomed.

ワイヤプローブを用いた微細貫通形状計測装置の開発

This paper describes the developed system to measure accuracy of the fine contour shape of the penetrated specimen. Examples, usually, the accuracy of the parts machined by wire EDM are measured with a projector. But it can not be useful to check the error of shape in a cross section at any desired height, except at the top and bottom surfaces of the specimen. The developed system uses the fine wire as a probe having partially convex shape. The wire probe moves along the programmed contour path, and approaches to the surface of specimen with 1μm step in a cross section at the desired height. The touching of the wire probe to the specimen is found from the wire displacement at the outside of the specimen. The wire displacement is detected with the developed measuring instrument composed with optical fibers and slits. Some difficulties to function this system are discussed and the countermeasures of them are proposed. And also the possibility and the method to use it for submicron measurement are discussed. It was found that this system is useful to measure the accuracy of specimen in a cross section at any height of specimen.

Design analysis of a composite L5-20 slit for x-ray beamlines at the Advanced Photon Source

White-beam slits are precision high heat load devices used on beamlines of the Advanced Photon Source (APS) to trim and shape the incoming x-ray beam before the beam is transmitted to other optical components. At the APS, the insertion devices that generate the x-ray beams are very powerful. For example, the heat flux associated with an x-ray beam generated by undulator A will be on the order of 220 W/mm2 at the L5-20 slit location (about 27.5 m away from the insertion device) at normal incidence. The total power is about 6 kW. Optical slits with micron-level precision are very difficult to design under such heat flux and total power considerations. A novel two-metal composite slit has been designed to meet the diverse thermal, structural, and precision requirements. A commercial code, ANSYS, has been used as the finite element source for the analysis of the optimized design for the set.

等間隔ピッチ信号とレーザビームの平行走査位置を同期させた光学式外径測定機

This development paper describes the optical measurement system of diametral dimension by parallel scanning of a laser beam. The measure is taken by counting the synchronous pulses with the scanning position of the beam. The pulse signal is generated with a linear scale composed of the optical slits at an equal space on the rotational scanning unit. Therefore a high-precision constant speed motor and fundamental optical components such as a scanning polygon mirror and an Fθ lens fall into disuse. Its compact size and omission of complicated electronic circuits for time-consuming calculation are also strong points of the developed measurement system.

The Cosharp Printer — Design Concept

This article gives a conceptual progress report on the development of the Cosharp Printer, proposed to the Technology Foundation of the Motion Picture/Television Industry by Richard Edlund of Boss Film. The name is an acronym descriptive of the product: Continuous Optical Slit High-speed Anamorphic Reduction Printer. It is universally accepted that 65mm original photography produces an image about three times the resolution of the same one originated in a 35mm print. However, for practical reasons it is necessary to make 35mm reduction prints for post-production purposes. The cost of this step is prohibitive; the quality of the resulting prints and the time taken to produce them mitigate against the process. This printer offers technical and economic resolution of these problems.

Measurement of turbulent wall velocity gradients using cylindrical waves of laser light

A new optical instrument has been developed for direct measurement of instantaneous velocity gradients at the bounding wall. Light emerging from two tiny optical slits in the surface is used to form a “fan of fringes” in the region very near the wall. Doppler frequency of the light scattered by the seed particles is directly proportional to the velocity gradient. The system has been used to measure the statistics of the streamwise and spanwise velocity gradients in a turbulent boundary layer. The streamwise and spanwise rms fluctuations were found to be 38% and 11% of the mean streamwise value respectively. The latter result is subject to a large uncertainty.

Slit width calibration with a radioactive photon source

Optical slits and similar small openings may be easily calibrated in width or area without the troublesome diffraction effects which occur at visible wavelengths and make accurate measurement very difficult. One employs photons of much shorter wavelengths, the soft X-rays emitted by a radioactive source, 55Fe for example. With such a source and a suitable photon detector, width calibrations to micrometer dimensions are quickly made.

Simple photographic method for producing narrow optical diffraction slits

Simple photographic method for producing narrow optical diffraction slits