A simple tandel electrometer circuit

A simple electrometer circuit is described, which makes use of two TANDELs connected in a bridge type circuit. The results show that an input resistance of 10¹² ohms can easily be obtained in a simple circuit, which is resistant to input voltage overloading and mechanical shocks. The circuit may be used as a simple direct reading electrometer having a sensitivity of about 1 V of the d-c input signal for full scale deflection. A satisfactory performace was found in the whole range of ambient temperatures used for testing, i.e. from 0°C to 40°C.This paper was presented at the Space Radio Communication Conference in Geneva on November 7, 1963.     

光纤探头烧结电路设计

为了满足烧结光纤探头的需要,设计了一种基于脉宽调制芯片CA1524的高压放电装置.首先通过推挽功率放大电路,将直流电逆变为高压交流电；然后经倍压整流得到2000多伏的直流电,最后连接电极棒进行高压放电.使用芯片LPC1768控制CA1524输出波形的占空比来改变放电强度,以及放电时间.     

Noise reduction in pulse-code-modulated images by optical regenerative repeaters

Digital signal transmission in electronic communication links provides the possibility of periodic reshaping of the electronic pulses by so-called regenerative repeaters, thereby keeping the signal above the noise level. This concept of noise minimization is applied to the optical transmission of pulse-coded images. Optical elements are described which correspond to the regenerative repeaters used in electronic transmission systems. They are based on holographic as well as incoherent methods. Examples illustrating the basic idea are provided.     

基于DVD读取头的光学探头电路设计

随着工业精密测量对于精度和分辨率的要求越来越高,光学探头在工业精密测量中得到了广泛的应用。由于DVD读取头的聚焦误差信号FES(Focus Error Signal)即S曲线的一部分与失焦距离成线性关系,因此稍作改进就可以做光学探头,用来进行微小位移的测量[1]。文中给出了其电路设计,该电路分成两个部分,一个是LD功率自动控制电路,一个是FES获取电路。经过实验测试,利用该电路可以获得良好的S曲线,可实现对微器件(几何尺寸数毫米至数微米,精度参数多为微纳米数量级)的精确测量。该电路设计具有结构简单、抗干扰能力强等突出优点。     

A simple tandel electrometer circuit part II

The properties of a simple electrometer circuit using a tandel are described in detail. The influence of changes in the external conditions (frequency and amplitude of heating voltage and ambient temperature) and in some important parameters of the circuit (load resistance and series capacity) on the properties of the circuit is shown as well as the influence of feedback which was introduced to decrease the input capacity of the circuit. It is shown how to form a bridge connection from two basic simple circuits and the advantages of such a connection are pointed out.The circuit described has a d-c input resistance of about 10¹³ for an input capacity of approx. 250 F. It can work with a symmetrical or asymmetrical input signal while the output may also be symmetrical or asymmetrical.     

一种简单的干涉光路

介绍了用反射镜和立方棱镜实现两束光相干涉的光路。     

A simple method for timing an XFEL source to high-power lasers

We propose a technique for timing an X-ray free-electron laser (XFEL) to a high-power conventional laser with femtosecond accuracy, yielding the relative jitter between pump and X-ray probe, and allowing sorting of experimental results over a certain time window. The same electron bunch is used to produce both an XFEL pulse and an ultrashort optical pulse by means of an optical radiator downstream of the X-ray undulator. Being produced by the same electron bunch, these pulses are perfectly synchronized. Cross-correlation techniques will allow to determine relative jitter between the optical pulse (and, thus, the XFEL pulse) and a pulse from an external pump-laser. Technical realization of the proposed timing scheme uses an optical-replica synthesizer setup to be installed after the final bunch-compression stage of the XFEL for electron bunch diagnostics purposes. A number of critical issues are quantitatively analyzed.     

介绍一种简单的光学模糊成像技术

本文介绍了一种光学成像技术,采用这种技术可以得到一张面目全非的照片。这张面目全非的照片经过处理后,又可恢复成原来的照片。这种技术具有一把钥匙开一把锁的特性,在某些场合具有特殊的用途。     

一种简单实用的光学滤波器

根据空间滤波特点,在普通单缝上增加两对挡光片,使之成为一种实用的光学滤波器。     

A simple model for the optical Bu modes inAV-BVI-CVII compounds

The eigenvalues of the optical modes of theAV-BVI-CVII compounds SbSI, SbSeI, BiSI, BiSeI, BiSBr, BiSeBr, and SbSBr in the paraelectric phase and the polarizationE c are calculated by use of a simple model fitted by the observed transverse mode frequencies. For the low-frequency mode theAV and theBVI ions are shown to vibrate simultaneously against theCVII ions. For the high-frequency mode the motion of theCVII ions is almost absent and theAV ions vibrate against theBVI ions.     

A simple Lorenz circuit and its radio frequency implementation

A remarkably simple electronic circuit design based on the chaotic Lorenz system is described. The circuit consists of just two active nonlinear elements (high-speed analog multipliers) and a few passive linear elements. Experimental implementations of the circuit exhibit the classic butterfly attractor and the hysteretic transition from steady state to chaos observed in the Lorenz equations. The simplicity of the circuit makes it suitable for radio frequency applications. The power spectrum of the observed oscillations displays a peak frequency as high as 930 kHz and significant power beyond 1 MHz.     

A simple thermal phase stabilizer for real-time optical fibre holographic interferometry

An optical fibre interferometer can be made to phase-stabilize by simply attaching a short length of one arm of the interferometer to a straight copper track and heating the track with an electric current. This feedback thermal stabilization scheme works well even for relatively short fibre lengths and there is no need to treat or unjacket the fibre. A fibre-optic Michelson interferometer stabilized by this method successfully provided object and reference beams for real-time holographic interferometric measurements of the distortion of heated test objects.     

A simple apparatus for the direct measurement of optical gain spectra

A simple apparatus which allows direct recording of optical gain and induced absorption spectra is presented. It makes use of the very sensitive method based on the modulation of the length of the illuminated sample surface. It can easily be assembled with elements usually present in any spectroscopy laboratory and does not need calibration. The sensitivity of the system and the main sources of error are analysed in detail.     

A simple GUI for modeling the optical properties of single metal nanoparticles

We present a graphical user interface, based on the modified long-wavelength approximation, to compute the optical properties of single metal nanoparticles of ellipsoidal geometry (spheres, rods, and disks). The user-friendly interface allows one to readily gauge the accuracy of results obtained using the modified long-wavelength approximation. For spherical particles, up to 10-nm diameter, we confirm that our approach yields an exact correspondence with Mie theory, and gives an approximation error of less than 15% for gold (silver) particles with diameters approaching 40 nm (26 nm). Results are shown to be sensitive to the source data for the optical constants for a given material. The modular nature of the simulation platform provides a quick and intuitive guide for optical characterization experiments.     

A simple formula for the fundamental optical absorption of alkali halide melts

Significant similarities — with respect to absorption of ultraviolet — between the crystalline and liquid phases of the alkali halides are considered. It is shown that a simple formula which emerged from an earlier application of local electron transfer concepts to the fundamental absorption of the alkali halide crystals appears to apply equally well (i.e. within experimental error) to their melts. This formula fits the observations relating to the fundamental absorption of five molten alkali halides and yields predictions for all the others — which will, it is hoped, stimulate experimental activity.     

A simple reflection-type two-dimensional refractive index profile measurement technique for optical waveguides

We report a new configuration of a reflection-type confocal scanning optical microscope system for measuring the refractive index profile of an optical waveguide. Several improvements on the earlier design are proposed; a light emitting diode at 650 nm wavelength instead of a laser diode or He-Ne laser is used as a light source for better index precision, and a simple longitudinal linear scanning and a curve fitting techniques are adapted instead of a servo control for maintaining an optical confocal arrangement. We have obtained spatial resolution of 800 nm and an index precision of 2 × 10⁻⁴. To verify the system’s capability, the refractive index profiles of a conventional multimode fiber and a home-made four-mode fiber were examined with our proposed measurement method.     

A simple optical method for the measurement of glass wool fiber diameter

An optical method for measuring glass wool fiber diameter has been proposed and discussed from the viewpoint of practical use. The method is based on both light scattering and light reflection on the glass wool. The method can measure the mean fiber diameter, d, in the area illuminated by laser light in realtime. The accuracy of the method, i.e., the dimensional resolution, was found to be about 0·7 μm within the diameter range of d7·0 μm.     

A simple optical method for measuring the vibration amplitude of a speaker

A simple optical method has been proposed for measuring the vibration amplitude of a speaker vibrating with a frequency of approximately 10 kHz. The method is based on a multiple reflection between a vibrating speaker plane and a mirror parallel to that speaker plane. The multiple reflection can magnify a dispersion of the laser beam caused by the vibration, and easily make a measurement of the amplitude. The measuring sensitivity ranges between sub-microns and 1 mm. A preliminary experiment verified the reliability of this method.