Portable three-wavelength standard for energy unit of pulse laser radiation

New instrument for applications in metrological measurements of laser pulse energy is presented. Due to its parameters, it can be used as a standard for energy unit of pulse laser radiation. The instrument consists of a control unit, three different sources of laser radiation, two detectors of optic...

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Дата:	2004
Автори:	Owsik, J., Zarwalska, A., Janucki, Ja., Samoylov, V.B.
Формат:	Стаття
Мова:	English
Опубліковано:	Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України 2004
Назва видання:	Semiconductor Physics Quantum Electronics & Optoelectronics
Онлайн доступ:	http://dspace.nbuv.gov.ua/handle/123456789/118177
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Назва журналу:	Digital Library of Periodicals of National Academy of Sciences of Ukraine
Цитувати:	Portable three-wavelength standard for energy unit of pulse laser radiation / J. Owsik, A. Zarwalska, Ja. Janucki, V.B. Samoylov // Semiconductor Physics Quantum Electronics & Optoelectronics. — 2004. — Т. 7, № 2. — С. 202-206. — Бібліогр.: 8 назв. — англ.

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Digital Library of Periodicals of National Academy of Sciences of Ukraine

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spelling	irk-123456789-1181772017-05-30T03:02:51Z Portable three-wavelength standard for energy unit of pulse laser radiation Owsik, J. Zarwalska, A. Janucki, Ja. Samoylov, V.B. New instrument for applications in metrological measurements of laser pulse energy is presented. Due to its parameters, it can be used as a standard for energy unit of pulse laser radiation. The instrument consists of a control unit, three different sources of laser radiation, two detectors of optical signal, and a laptop. The whole system can be easily transported enabling one to perform measurements in situ, at customers, and not only in laboratory conditions. A method of measurements used in the standard operation is described. Main characteristics of the standard are shown. Methods enabling calculations of measurement uncertainties during laser energy meter calibration by means of our standard are also presented. 2004 Article Portable three-wavelength standard for energy unit of pulse laser radiation / J. Owsik, A. Zarwalska, Ja. Janucki, V.B. Samoylov // Semiconductor Physics Quantum Electronics & Optoelectronics. — 2004. — Т. 7, № 2. — С. 202-206. — Бібліогр.: 8 назв. — англ. 1560-8034 PACS: 06.20.Fn, 07.60.-j http://dspace.nbuv.gov.ua/handle/123456789/118177 en Semiconductor Physics Quantum Electronics & Optoelectronics Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України
institution	Digital Library of Periodicals of National Academy of Sciences of Ukraine
collection	DSpace DC
language	English
description	New instrument for applications in metrological measurements of laser pulse energy is presented. Due to its parameters, it can be used as a standard for energy unit of pulse laser radiation. The instrument consists of a control unit, three different sources of laser radiation, two detectors of optical signal, and a laptop. The whole system can be easily transported enabling one to perform measurements in situ, at customers, and not only in laboratory conditions. A method of measurements used in the standard operation is described. Main characteristics of the standard are shown. Methods enabling calculations of measurement uncertainties during laser energy meter calibration by means of our standard are also presented.
format	Article
author	Owsik, J. Zarwalska, A. Janucki, Ja. Samoylov, V.B.
spellingShingle	Owsik, J. Zarwalska, A. Janucki, Ja. Samoylov, V.B. Portable three-wavelength standard for energy unit of pulse laser radiation Semiconductor Physics Quantum Electronics & Optoelectronics
author_facet	Owsik, J. Zarwalska, A. Janucki, Ja. Samoylov, V.B.
author_sort	Owsik, J.
title	Portable three-wavelength standard for energy unit of pulse laser radiation
title_short	Portable three-wavelength standard for energy unit of pulse laser radiation
title_full	Portable three-wavelength standard for energy unit of pulse laser radiation
title_fullStr	Portable three-wavelength standard for energy unit of pulse laser radiation
title_full_unstemmed	Portable three-wavelength standard for energy unit of pulse laser radiation
title_sort	portable three-wavelength standard for energy unit of pulse laser radiation
publisher	Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України
publishDate	2004
url	http://dspace.nbuv.gov.ua/handle/123456789/118177
citation_txt	Portable three-wavelength standard for energy unit of pulse laser radiation / J. Owsik, A. Zarwalska, Ja. Janucki, V.B. Samoylov // Semiconductor Physics Quantum Electronics & Optoelectronics. — 2004. — Т. 7, № 2. — С. 202-206. — Бібліогр.: 8 назв. — англ.
series	Semiconductor Physics Quantum Electronics & Optoelectronics
work_keys_str_mv	AT owsikj portablethreewavelengthstandardforenergyunitofpulselaserradiation AT zarwalskaa portablethreewavelengthstandardforenergyunitofpulselaserradiation AT januckija portablethreewavelengthstandardforenergyunitofpulselaserradiation AT samoylovvb portablethreewavelengthstandardforenergyunitofpulselaserradiation
first_indexed	2025-07-08T13:31:09Z
last_indexed	2025-07-08T13:31:09Z
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fulltext	Semiconductor Physics, Quantum Electronics & Optoelectronics. 2004. V. 7, N 2. P. 202-206. © 2004, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine202 PACS: 06.20.Fn, 07.60.-j Portable three-wavelength standard for energy unit of pulse laser radiation J. Owsik, A. Zarwalska, Ja. Janucki, V.B. Samoylov* Institute of Optoelectronics, Military University of Technology 2, Kaliskiego St., 00908 Warsaw, Poland, E-mail: jowsik@wat.waw.pl *Institute of Physics NAS of Ukraine, 46, Prospekt Nauki, 03022, Kiev, Ukraine Phone: +380 (44) 265 79 52; fax: +380 (44) 265 15 89, E-mail: samoylov@iop.kiev.ua Abstract. New instrument for applications in metrological measurements of laser pulse en- ergy is presented. Due to its parameters, it can be used as a standard for energy unit of pulse laser radiation. The instrument consists of a control unit, three different sources of laser radiation, two detectors of optical signal, and a laptop. The whole system can be easily transported enabling one to perform measurements in situ, at customers, and not only in laboratory conditions. A method of measurements used in the standard operation is de- scribed. Main characteristics of the standard are shown. Methods enabling calculations of measurement uncertainties during laser energy meter calibration by means of our standard are also presented. Keywords: laser, energy, metrology, standard, unit. Paper received 29.12.03; accepted for publication 17.06.04. 1. Introduction In the second half of nineties, a system for metrology protection of laser technique in Poland was suggested [1]. It was established at the Institute of Optoelectronics (IOE) and based on two medium-level stationary stand- ards of power and energy units of laser radiation. Uncer- tainty of measurements connected to the standard of power unit amounted up to 0.2%, while for the standard of en- ergy unit � 0.85%. In 1998, a new idea of laser metrol- ogy protection system in Poland appeared, grounded on primary standard for radiant power unit based on the absolute cryogenic radiometer [2]. The radiometer with a very low uncertainty (expanded uncertainty for k = 2 equals 0.05%) of measurement has been recently installed at the Central Office of Measures (COM). This system for transfer of units of radiative energy and power, is similar to systems developed earlier in other leading cen- tres dealing with radiative calibration of heat-flux detec- tors (the Physikalisch-Technische Bundesanstalt - PTB, Germany, and the National Institute of Standards and Technology � NIST, the United States). Both of these systems [3�5] use high accuracy cryogenic radiometers as primary standards for calibrations systems. In both laboratories, the trap detectors, well-known and described elsewhere [6], form the next level of the calibration chain. The same solution has been adapted to our system (in [7] details of common calibrations of Polish (COM and IOE) and Swedish trap detectors against similar cryogenic ra- diometer mounted at SP Institute in Bors, Sweden are presented). Subsequent stages of the calibration chain characterised by higher uncertainty of measurement de- veloped at the IOE apparently differ from solutions used in other laboratories, since we established two groups of working standards: the local and portable ones. This resulted from the analysis showing that further develop- ment of calibration standards for metrology protection system of laser technique will be focused on three differ- ent directions. Those should be: microwatt standards for telecommunication, powerful kilowatt standards for in- dustry, and mobile compact medium-level standards for units of energy or power of laser radiation for any appli- cation. The present work deals with such a small, com- pact, mobile standard of unique capabilities intended for laser energy measurements with reasonably low uncer- tainty of measurements. 2. Structure of the standard As it has been stated in the previous section, the instru- ment should meet all the most common demands, as far as the metrology protection system for laser technique is J. Owsik et al.: Portable three-wavelength standard for energy unit of pulse laser radiation 203SQO, 7(2), 2004 considered. If so, it has to ensure calibration or testing at wavelengths mostly used in laser devices applied in in- dustry, medicine, military applications, and science as well. That is why the standard has been equipped with Nd:YAG laser (λ = 1.06 µm), frequency converter dou- bling Nd:YAG frequency (λ = 0.53 µm), and erbium la- ser (λ =1.54 µm). Two calorimetric measuring transduc- ers have been chosen as radiation detectors. These en- ergy meters have flat spectral characteristics and they withstand high energy levels of input signals. The stand- ard is computer controlled and a special software packet has been prepared for its operation. Optical scheme of the standard is shown in Fig. 1. 3. Measuring transducer Structural arrangement of the calorimetric measuring transducer is presented in Fig. 2. It consists of two calori- metric receivers: the working and compensation ones. Each receiver consists of nickel-deposited copper cone- shape cavity with substitution manganin winding assigned for transducer calibration, copper compensation cone, and copper-constantan thermopiles. Both receivers are built in a passive thermostat mounted in two metallic housings. In front of the receivers, a diaphragm is placed, which reduces influence of convection flows and makes transducer operation more reliable. Principle of operation of the measuring transducer is based on transformation of laser radiation energy into thermoelectromotive force, which is proportional to op- tical energy. The measured radiation enters working cone 2, which is heated up. This heat is then transmitted to the compensation cone 4. Heating of the compensa- tion cone is registered by thermopiles 5, �hot� outputs of which are placed on the cone 4, while �cold� ones � into thermostat 11. The thermopiles are connected according to a differ- ential scheme. Output signals from them are then deliv- ered to an amplifier and gained about 103 times. Electri- cal scheme of the transducer enables it to precise electri- cal calibration, which should be performed once a year. Electrical scheme of MT-1 transducer is shown in Fig. 3. The measuring transducer has been investigated in order to estimate damage thresholds due to over-expo- sure of laser radiation. Apart from laser energies, two factors have been taken into consideration, i.e. beam di- ameter and laser pulse duration. Measurements were car- ried out using Nd lasers. Results of measurements are shown in Fig. 4. The chart should be read as follows: if, during measurement, values are too large (high laser en- ergies) or too low (short pulses or small beam diameters) as compared to depicted values in the graph - errors and uncertainties related to measurements will exceed allowed levels for a specified type of the instrument. In some ex- treme cases, hard damage and disorder of the calorim- eter can happen. 11 12 13 1 2 3 4 5 6 9 7 8 10 Fig. 1. Optical layout of the standard; MT-1, MT-2 � calorimet- ric measuring transducers, FCR � frequency converter. Fig. 2. Calorimetric transducer structure; 1 � diaphragm, 2 � receiving cone, 3 � substitution winding, 4 � compensation cone, 5 � thermopiles, plate with resistors, 7 � inner housing, 8 � outer housing, 9 � socket, 10 � processing & control plate, 11 � passive thermostat, 12 � input window of compensating receiver, 13 � input window of working receiver. Attenuator 2 Tested Meter MT-1 Beam splitters Lasers FCR Aperture l l = 1.06 1.54 = 0.53 m, m mµ µ µ Attenuator 1 MT-2 Tp1 Z1 II Tp2 Z2 II R2 R1 S1 S2 Processing and control plate Working receiver Housing Compensation receiver Internal screen Fig. 3. Electrical scheme of MT-1 transducer. 204 SQO, 7(2), 2004 J. Owsik et al.: Portable three-wavelength standard for energy unit of pulse laser radiation 4. Operation of the standard Firstly, if the instrument is to operate as a standard for energy unit of laser radiation, it has to receive this en- ergy value from a standard of much less uncertainty of measurements. In our case, MT-1 transducer is given an energy unit from primary standard of mean power and energy unit of laser radiation. Energy unit is given in the form of coefficient of equivalence between laser energy for the wavelength 0.5 µm and electrical energy of ap- proximately the same value. Calibration method applied here is based on commonly used electrical substitution of optical energy (electrical and optical heats are compared). This value of energy unit is then being stored for a period of 12 months after which the next calibration must be performed. Of course, for metrological purposes, the cali- bration chain should be assured, and, if a suitable stand- ard is not available, the so-called intercomparisons are to be carried out. Typical proceeding aimed at calibration of an en- ergy meter can be divided into some steps, each of them being computer controlled. At the beginning, a proper configuration of the standard must be chosen (operator has to install a laser of the specified wavelength). After 15-minute warming up the standard, its auto-calibration starts. As a rule, it comprises electrical calibration and optical one. In these processes, calorimetric transducers, MT-1 and MT-2, are firstly electrically calibrated. The electrical equivalence factor is found. In order to decrease uncertainty, this calibration can be repeated several times. Optical calibration occurs in the next step, and operator can proceed it up to 8 times. As a result, MT-2 transducer becomes calibrated against MT-1 one � opti- cal equivalence factor between these two transducers is found. The auto-calibration procedure is then completed, and the next MT-1 transducer is removed from the stand- ard configuration. MT-1 calorimeter is now replaced with unknown tested laser energy meter, which is to be calibrated. La- ser pulses in the specified energy range are subsequently generated, and calibration starts. The calibration is per- formed using MT-2 readings, which are then compared to the readings of the tested meter. The number of com- parisons depends only on an operator, but typically it equals to 10. The ten-fold repetition of measurements makes the uncertainty of calibration more reliable. The calibration factor and its uncertainty as well as the rela- tive error of the calibrated energy meter and its uncer- tainty are the final results of this calibration procedure. 5. Main operational and metrological charac- teristics of the standard Operational capabilities of the instrument are very inter- esting, because there are three laser sources used in the standard, calibration can be carried out in several en- ergy ranges of the lasers, and MT-1 and MT-2 calorim- eters are not spectrally selective (their spectral charac- teristics are flat from 0.4 to 2 µm). Main operational char- acteristics are shown in Tables 1, 2, and 3. The general view of the instrument is presented in Fig. 5. As it can be seen from Fig. 5, the standard, as a whole, is a medium-sized compact instrument (view of a laptop makes this statement evident). The standard can be dis- mounted into parts, then put into the three normal-sized cases and easily transported elsewhere. The total weight of the instrument does not exceed 40 kg. Apart from operational parameters, metrological char- acteristics of the instrument are also very important. The inherent standard uncertainty of measurements with this instrument, u(ESSE), resulting from and related to a proc- ess of energy unit transfer from the higher level standard and connected to standard readings equals 1%. As it was mentioned above, the calibration factor (CF) and the relative error δ of energy meter under calibration (EM) together with combined standard uncertainties of these quantities uC(CF) and uC(δ) are final results of the calibration process. Methods to calculate these uncer- tainties and errors were elaborated according to [8]. Errors being made during measurements are sources of uncertainties of CF factor and the relative error δ as well. Estimation of uncertainties of measurements is per- formed via two ways: A-type estimation � statistical analy- sis of single measurement results series, and B-type esti- mation � with use of other than statistical methods (for example on the base of catalogue data, supplier data, calibration certificate and so on). Typical procedure, when calculating uncertainties of the factor CF and the relative error δ, needs some formulae to be applied and they are shown below, after some definitions: i EME is EM reading in the i-th measurement, i SSEE is reading of the standard in the i-th measure- ment, n is the number of measurements during calibration, SSEE is arithmetic mean of the standard readings, EME is arithmetic mean of EM readings, ( )CFuA is A-type standard uncertainty of CF, ( )CFuB is B-type standard uncertainty of CF, ( )δAu is A-type standard uncertainty of the error δ, ( )δBu is B-type standard uncertainty of the error δ, ( )CFuC is combined standard uncertainty of CF, ( )δCu is combined standard uncertainty of δ, Table 1. Characteristics of the standard equipped with Nd:YAG laser Wavelength, µm 1.064 Energy range, mJ 3�5 60�75 150�180 Beam diameter, mm 3 Energy density 0.05 0.85 2.10 in laser beam, J/cm2 Pulse duration, ns 40 J. Owsik et al.: Portable three-wavelength standard for energy unit of pulse laser radiation 205SQO, 7(2), 2004 ( )EMEu is standard uncertainty of EM readings ( )SSEEu is standard uncertainty of SSE readings, EMEδ is resolution of EM readings (from EM manual). The set of necessary formulae leading to calculation of the calibration factor and relative error as well as to their uncertainties is as follows: Arithmetic means can be derived as: ∑ = = n i i SSESSE E n E 1 1 , (1) ∑ = = n i i EMEM E n E 1 1 . (2) The calibration factor CF: ∑ = = n i i EM i SSE E E n CF 1 1 . (3) Standard uncertainty of EM readings: ( ) 3 EM EM E Eu δ = . (4) A-type standard uncertainty of the calibration factor CF: ( )∑=         − − = n 1i 2 1 1 )( CF E E nn CFu i EM i SSE A . (5) B-type standard uncertainty of the calibration factor CF: ( ) ( ) ( )[ ] ( )[ ] . 1 2 2 2 2 2 SSE PPE PPE PPE SSE B Eu E Eu E E CFu ⋅    +⋅         −= = (6) Combined standard uncertainty of the factor CF: ( ) ( )[ ] ( )[ ]22 CFuCFuCFu BAC += . (7) Table 2. Characteristics of the standard equipped with Nd:YAG laser and frequency converter Wavelength, µm 0.53 Energy range, mJ 10�15 40�55 Beam diameter, mm 3 Energy density 0.15 0.55 in laser beam, J/cm2 Pulse duration, ns 40 t , s 1 10 � 10 10 10 10 10 10 10 3 4 5 6 7 8 9 10 Beam diameter, mm 100 50 10 5 1 0.5 0.1 R ad ia tio n en er gy , J �1 �3 �4 �5 �6 �7 �8 �2 imp Fig. 4. Maximum allowed values for laser radiation energy ver- sus beam diameter and pulse duration. Table 3. Characteristics of the standard equipped with erbium laser Wavelength, µm 1.54 Energy range, mJ 5�10 40�50 70�90 Beam diameter, mm 4 Energy density 0.06 0.32 0.55 in laser beam, J/cm2 Pulse duration, ms 1.5 1 2 3 4 5 Fig. 5. A picture of the standard for energy unit of pulse laser radiation; 1 � MT-1 calorimetric transducer, 2 � main body of the standard comprising electronics, optical tract, and MT-2 calorimetric transducer, 3 � frequency converter, 4 � Nd:YAG laser, 5 � laptop with main menu of the software. 206 SQO, 7(2), 2004 J. Owsik et al.: Portable three-wavelength standard for energy unit of pulse laser radiation Relative error of EM: %1001 1 1 ⋅                 −= ∑ = n i i SSE i EM E E n δ . (8) A-type standard uncertainty of the error δ is as fol- lows: ( ) ( ) %100 1 %100 1 1 2 ⋅                   −         −− = ∑ = nn E E u n i i SSE i EM A δ δ . (9) B-type standard uncertainty of the relative error : ( ) ( )[ ] ( ) ( )[ ] .%100 1 2 2 2 2 2 × ×           ⋅         −+⋅    = = SSE SSE EM EM SSE B Eu E E Eu E u δ (10) Combined standard uncertainty of relative error δ : ( ) ( )[ ] ( )[ ]22 δδδ BAC uuu += (11) Based on these formulae, calibration factors and rela- tive errors of any laser energy meters being calibrated against this standard can be found. 6. Conclusions The instrument can be used as the metrological standard in calibration of energy meters for the lasers of 1.06 µm, 0.53 µm, and 1.54 µm wavelengths, respectively. The lat- ter wavelength is eye-safe one. Generally, the instrument can be used for checking energy meters at any wavelength within the range 0.40 to 2 µm. In the process of energy unit transfer, it uses a comparative method. References 1. J. Owsik, A basis for metrological protection of energy laserometry // J.Techn.Phys., 38(1), pp. 97-109 (1997). 2. J. Pietrzykowski, Primary standard for radiant power based on cryogenic radiometer (in Polish), in Proceedings of Polish Na- tional Metrology Congress, KKM�98, Gdansk. 15-18.09.1998. 3. K.D. Stock and H. Hofer, Present state of the PTB primary standard for radiant power based on cryogenic radiometry // Metrologia, 30, pp. 291-296 (1993). 4. T.R.Gentile et al., Calibration of a pyroelectric detector at 10.6 µm with the National Institute of Standards & Technol- ogy high accuracy radiometer // Appl.Opt., 36(16), pp. 3614- 3621 (1997). 5. A.V.Murthy and B.K. Tsai and R.D. Saunders, Radiative calibration of heat-flux sensors at NIST: facilities and tech- niques // Journal of Research of the National Institute of Standards and Technology, 105(2), pp. 293-305 (2000). 6. J. Pietrzykowski, Self-calibrated photodiodes and their ap- plications, in Proc. of optoelectronics Metrology Conf., Lancut, Poland, 28-30.09.1998. 7. G. Werner and L. Liedquist, Calibration of radiant laser power with a cryogenic radiometer at visible wavelengths and at 10.6 µm // SPIE Proceedings, 4018, pp. 73-78 (1998). 8. Guide to the expression of uncertainty in measurement, Ge- neva, Switzerland, ISO (1993).

Portable three-wavelength standard for energy unit of pulse laser radiation

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