A Calorimeter for High-Power CW Lasers

Smith, Richard L.; Russell, Thomas W.; Case, William E.; Rasmussen, A. L.

doi:10.1109/tim.1972.4314062

Cited by 33 publications

(14 citation statements)

References 3 publications

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“…In calorimetric principle [59,60], laser power is allowed to fall on a conical dump made of black anodized copper material [refer Fig.12] for maximum absorption with minimum loss. A series of K type thermocouples are fixed at the other surface of the cone for measuring the temperature rise.…”

Section: Laser Power and Pulse Shape Measurementmentioning

confidence: 99%

Overview of Optical Techniques for Characterization of High-Power Infrared Gas Lasers

et al. 2015

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High power lasers typically form a multidisciplinary technological area laced with innumerable challenges in its realization as a practical system. The prime amongst them are infrared gas laser sources such as Carbon-di-Oxide Gas Dynamic Laser, Hydrogen Fluoride, Deuterium Fluoride Laser and Chemical Oxygen Iodine Laser etc. Each of these laser systems is associated with a unique as well as complex active medium environment involving intense interaction between lasing and pumping species under specific gas dynamic conditions. The parameters viz. specie concentration of the lasing, pumping mediums and other by-products, medium homogeneity, individual constituent gas flow rate, pressure and temperature at critical locations and cavity Mach number are very crucial in determining the output of the gas laser system. It is essential to determine these parameters non-intrusively, with necessary precision so as to optimize these lasers especially in case of largescale systems. Thus, the focus of this paper is to review and discuss the existing applicable optical detection methodologies ranging from the more established methods such as optical absorption/emission spectroscopy to very contemporary like Raman spectroscopy, cavity ring down spectroscopy, laser induced fluorescence/ planer laser induced fluorescence etc., which are relevant for the diagnostic needs of gas lasers.

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Section: Laser Power and Pulse Shape Measurementmentioning

confidence: 99%

Overview of Optical Techniques for Characterization of High-Power Infrared Gas Lasers

et al. 2015

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“…High-energy laser energy meters are calibrated mainly via two methods: (1) optical element spectrometry accompanied with a standard energy meter [1,2], and (2) replacement of laser energy by electric energy and transforming electric energy to heat energy by wrapping heating wire on the absorber or installing a high-power halogen tungsten lamp in the absorber [3][4][5][6][7][8]. The first method is simple but necessitates a laser source and a standard high-power energy meter, but these two devices in the high-power and high-energy field are rare at present.…”

Section: Introductionmentioning

confidence: 99%

Technology for radiation efficiency measurement of high-power halogen tungsten lamp used in calibration of high-energy laser energy meter

Sun

et al. 2015

Appl. Opt.

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The calibration method using a high-power halogen tungsten lamp as a calibration source has many advantages such as strong equivalence and high power, so it is very fit for the calibration of high-energy laser energy meters. However, high-power halogen tungsten lamps after power-off still reserve much residual energy and continually radiate energy, which is difficult to be measured. Two measuring systems were found to solve the problems. One system is composed of an integrating sphere and two optical spectrometers, which can accurately characterize the radiative spectra and power-time variation of the halogen tungsten lamp. This measuring system was then calibrated using a normal halogen tungsten lamp made of the same material as the high-power halogen tungsten lamp. In this way, the radiation efficiency of the halogen tungsten lamp after power-off can be quantitatively measured. In the other measuring system, a wide-spectrum power meter was installed far away from the halogen tungsten lamp; thus, the lamp can be regarded as a point light source. The radiation efficiency of residual energy from the halogen tungsten lamp was computed on the basis of geometrical relations. The results show that the halogen tungsten lamp's radiation efficiency was improved with power-on time but did not change under constant power-on time/energy. All the tested halogen tungsten lamps reached 89.3% of radiation efficiency at 50 s after power-on. After power-off, the residual energy in the halogen tungsten lamp gradually dropped to less than 10% of the initial radiation power, and the radiation efficiency changed with time. The final total radiation energy was decided by the halogen tungsten lamp's radiation efficiency, the radiation efficiency of residual energy, and the total power consumption. The measuring uncertainty of total radiation energy was 2.4% (here, the confidence factor is two).

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“…Such devices measure the temperature rise of the liquid drawing away the heat delivered by the incident radiation, which is correlated to the absorbed power. Smith et al [3] built a water-cooled high-power laser calorimeter capable of measurements up to 1 MJ. Emmony and Bunn [4] proposed a flowing water calorimeter capable of measurements up to 50 W. Fisk and Gusinow [5] designed a circulated liquid, volume absorbing calorimeter for use over a wide range of wavelengths.…”

Section: Introductionmentioning

confidence: 99%

Foam-based optical absorber for high-power laser radiometry

Ramadurai

Cromer

et al. 2007

Appl. Opt.

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We report damage threshold measurements of novel absorbers comprised of either liquid-cooled silicon carbide or vitreous carbon foams. The measurements demonstrate damage thresholds up to 1.6 ϫ 10 4 W͞cm 2 at an incident circular spot size of 2 mm with an absorbance of 96% at 1.064 m. We present a summary of the damage threshold as a function of the water flow velocity and the absorbance measurements. We also present a qualitative description of a damage mechanism based on a two-phase heat transfer between the foam and the flowing water.

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A Calorimeter for High-Power CW Lasers

Cited by 33 publications

References 3 publications

Overview of Optical Techniques for Characterization of High-Power Infrared Gas Lasers

Overview of Optical Techniques for Characterization of High-Power Infrared Gas Lasers

Technology for radiation efficiency measurement of high-power halogen tungsten lamp used in calibration of high-energy laser energy meter

Foam-based optical absorber for high-power laser radiometry

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