Gold-coated copper cone detector as a new standard detector for F2 laser radiation at 157 nm

A new standard detector for high-accuracy measurements of F2 laser radiation at 157 nm is presented. This gold-coated copper cone detector permits the measurement of average powers up to 2 W with an uncertainty of approximately 1%. To the best of our knowledge, this is the first highly accurate standard detector for F2 laser radiation for this power level. It is fully characterized according to Guide to the Expression of Uncertainty in Measurement of the International Organization for Standardization and is connected to the calibration chain for laser radiation established by the German National Metrology Institute.     

Method of Reducing the Error of Transferring the Size of a Unit of Laser Radiation Energy

A method is considered of reducing the error of transferring the size of a unit of laser radiation energy for a secondary standard of the units of average power and energy of laser radiation by using the readings of a relative-level sensor. A procedure is developed for processing the readings of this sensor.     

Influence of a Jump in the Power of Laser Radiation on Its Measurement

Simulation and investigation of the effect of an isolated jump on realization of the unit of power of laser radiation and dissemination of the size of the unit are considered. Results are obtained by means of a newly developed algorithm that characterizes the behavior of the mean value of a signal and the standard deviation of a system as functions of the parameters of a jump in the power of laser radiation and the length and amplitude of the jump. If information concerning the time when a jump occurs is available, the proposed algorithm makes it possible to take into account how a jump affects the ultimate result of a measurement.     

Increasing the accuracy of energy and average-power measurement of high-level laser radiation

A possible way to increase measurement accuracy, the design principle, research methods, the characteristics of a precision calorimetric system calibrated electrically by the substitution method, and verification equipment for instruments for measurement of high energy levels and the average power of laser radiation are examined. Translated from Izmeritel'naya Tekhnika, No. 5, pp. 39–43, May, 2000.     

Measurement of average power of excimer-laser radiation

Measurement of the average power of laser radiation in the ultraviolet region is examined. The characteristics of working and standard instruments are presented. Translated from Izmeritel'naya Tekhnika, No. 7, pp. 28–30, July, 2000.     

Silicon Carbide-Based Extreme Environment Hybrid Design Temperature Sensor Using Optical Pyrometry and Laser Interferometry

To the best of the authors' knowledge, proposed and demonstrated is the first extreme environment temperature sensor using Blackbody (BB) radiation of a high-temperature material optical chip for coarse temperature measurement and classical Fabry-Perot (FP) laser interferometry via the same chip for fine temperature measurement. Such a hybrid design sensor can be used to accurately measure temperatures in excess of 750°C such as needed for gas turbines in power plants and aircraft engines. The proposed sensor is designed and demonstrated using an all-Silicon Carbide (SiC) probe for temperatures from 795°C to 1077°C with an estimated average measurement resolution of 0.1°C.     

To simulate blackbody radiation frequency shift in cesium fountain frequency standard with CO2 laser.

An experimental scheme to simulate the Blackbody radiation (BBR) frequency shift with carbon dioxide (CO2) laser in cesium fountain frequency standard is proposed. The alternative (ac) electric field from a CO2 laser with 10.6 microm wavelength causes the similar ac Stark shift of the clock transition frequency, but with much higher intensity than BBR power intensity at about room temperature. This scheme provides a simple, new method for measuring the BBR frequency shift in fountain clock. It provides the possibility to explain the difference of BBR shifts in Cs fountain clocks between two measurement methods.     

Non-Selective Standard Indicator for the Average Power of Laser Radiation

A technical solution for the average power laser radiation standard applied to the ultraviolet range is suggested and characteristics of the standard are provided.__________Translated from Izmeritelnaya Tekhnika, No. 2, pp. 32–35, February, 2005.     

To simulate blackbody radiation frequency shift in cesium fountain frequency standard with CO/sub 2/ laser

An experimental scheme to simulate the blackbody radiation (BBR) frequency shift with carbon dioxide (CO/sub 2/) laser in cesium fountain frequency standard is proposed. The alternative (ac) electric field from a CO/sub 2/ laser with 10.6 /spl mu/m wavelength causes the similar ac Stark shift of the clock transition frequency, but with much higher intensity than BBR power intensity at about room temperature. This scheme provides a simple, new method for measuring the BBR frequency shift in fountain clock. It provides the possibility to explain the difference of BBR shifts in Cs fountain clocks between two measurement methods.     

Unification of measurements of the average power of optical radiation in fiber-optic transmission systems

The current status of measurement uniformity, the design and characteristics of new standard calorimeters and high-precision apparatus, and a hierarchical testing sequence are discussed in application to instruments for measuring the average power of optical radiation in fiber-optic transmission systems. Translated from Izmeritel'naya Tekhnika, No. 8, pp. 31–37, August, 2000.     

Elements in the determination of instability in the intensity of laser radiation

The article presents a formula for estimating the component of uncertainty in the measurement of the relative statistical fluctuation of the power of laser radiation caused by a finite number of measurements of power on the basis of which instability is determined. The influence of drift on the measured radiation power is established and a formula for adding the drift and fluctuation components of the relative statistical fluctuation is checked. __________ Translated from Izmeritel’naya Tekhnika, No. 11, pp. 28–32, November, 2006     

基准转换标准器在多系统集成中的应用

使用经纬仪、激光跟踪仪进行协同测量时需要对不同测量系统的测量基准进行基准转换,传统基准转换手段较为繁琐耗时.针对此问题,设计了一种新型便携式基准转换标准器,该标准器由基准转换组件、转向组件和三脚架组成,通过基准板上的测量靶点及立方镜构建坐标系,实现基准转换.经验证:该标准器在不同姿态下的平均位置偏差小于0.01 mm,...     

A Method of Attenuating High-Power Laser Radiation with 1.06 μm Wavelength Using a Diffraction Grating

Measurement Techniques - A method of attenuating high-power laser radiation using a small metal diffraction grating as an attenuator for power measurement was analyzed. The thermal operating modes...     

A Laser Microcalorimeter

A new type of microcalorimeter as the laser power standard in Japan has been developed at the Electrotechnical Laboratory. This is a double calorimeter in which the laser power is measured by a dc substitution method using the thermopile unit, and simultaneous measurement is also made using the Peltier cooling-type calorimeter by dc substitution. The CW power of the gas laser (He-Ne) is controlled with high stability (±0.05 percent) by the automatic power control system using the Faraday rotation component. By this method and equipment, the "effective efficiency" of the standard thermopile unit is determined precisely. The errors in this microcalorimetric technique are investigated with the aid of heat flow analysis and auxiliary experiments. As a result, the absolute accuracy of the CW power measurement of laser beams (6328?, 1.15?) is evaluated with high accuracy better than 0.5 percent. The experiments have been successful at 6328? and 1.15 ?, and this method is considered to be available at the region of infrared and far-infrared wavelength.     

Absolute measurement of F2-laser power at 157 nm

We report a comparison of laser power measurements at the F2-laser wavelength of 157 nm made at two facilities of the Physikalisch-Technische Bundesanstalt (PTB), the German national metrology institute. At the PTB laboratory at the electron storage ring BESSY II in Berlin, the scale for laser power was directly traced to a cryogenic radiometer operating at 157 nm, whereas at the PTB laser radiometry facility in Braunschweig the calibration of transfer detectors was performed with a newly developed standard for laser power at 157 nm, which is traceable in several steps to a cryogenic radiometer operating at 633 nm. The comparison was performed under vacuum conditions with laser pulse energies of approximately 10 microJ, however with different average powers because different primary standard radiometers were used. The relative deviation for the responsivity of the transfer detector was 4.8% and thus within the combined standard uncertainty.     

Optico-acoustic characterization of the fractal structure of radiation from a laser with unstable resonator

The thermooptical excitation of sound in a liquid by fluctuating laser radiation with sine-modulated intensity is studied theoretically. The intensity is randomly distributed over the beam cross section. It is assumed that the random processes are homogeneous and that the spatial spectrum of intensity fluctuations obeys a power fractal law. Possibilities for the optico-acoustic characterization of the fractal radiation structure of a laser with unstable resonator are discussed.     

Trapping and manipulating gas bubbles in water with ultrashort laser pulses at a high repetition rate

We have experimentally observed the trapping of a gas bubble in water by focused laser radiation. The optical trap was provided by 200-fs pulses of a Ti-sapphire laser operating at a repetition rate of 100 kHz. The laser radiation was focused in water by an objective with a numerical aperture of 0.5. The trapping force in water is estimated as ∼200 pN at an average laser power of 20 mW, which is by two orders of magnitude greater than the efficiency of a traditional laser tweezers. The trapping force arises upon local heating of gas inside a bubble due to nonlinear absorption in the focal region.     

A theoretical study of the metrological characteristics of a calibrated fresnel attenuator of the beam power of laser radiation

A theoretical investigation of the metrological characteristics of a precision Fresnel attenuator is performed for the purpose of determining whether it can be employed as a comparison standard intended for comparing the domestic primary standard of the unit of mean power of continuous laser radiation with an absolute cryogenic radiometer.     

Coherent differential absorption lidar measurements of CO2

A differential absorption lidar has been built to measure CO2 concentration in the atmosphere. The transmitter is a pulsed single-frequency Ho:Tm:YLF laser at a 2.05-microm wavelength. A coherent heterodyne receiver was used to achieve sensitive detection, with the additional capability for wind profiling by a Doppler technique. Signal processing includes an algorithm for power measurement of a heterodyne signal. Results show a precision of the CO2 concentration measurement of 1%-2% 1sigma standard deviation over column lengths ranging from 1.2 to 2.8 km by an average of 1000 pulse pairs. A preliminary assessment of instrument sensitivity was made with an 8-h-long measurement set, along with correlative measurements with an in situ sensor, to determine that a CO2 trend could be detected.     

复杂结构体的声辐射模态远场计算方法

声辐射模态在主动结构声控制领域取得了满意的噪声控制效果,但缺乏有效简便的远场测量或计算方法已成为其进一步发展的瓶颈。基于远场封闭包络与结构表面辐射声功率相等,借助声传递矩阵的概念,将声辐射模态的求解转换到流体域进行求解,获得了一种通用的任意结构远场声辐射模态求解方法。为了验证方法的可行性,利用不同的场点包络形状、不同距离的场点以及不同的场点数目对其性能进行分析,主要包括结构辐射声功率、声辐射模态幅值、声辐射模态效率。利用获得的声辐射模态计算脉动球的辐射声功率,并与其理论解进行比较,计算结果显示不同的场点状态对辐射声功率的影响较小,所获取的声辐射模态和辐射效率具有较高的可信度。同时,本方法可为远场测量声辐射模态提供理论参考。