Study Of Inspection/Calibration Technology For Micro-Energy Laser

Laser radiation metrology is one of the most fundamental parts of optical metrology. It mainly involves metrology measurement of radiation parameters for laser itself and measurement apparatus for laser performance parameters. As laser technology develops in different application fields, laser radiation metrology is progressing from traditional radiation metrology to metrology for laser radiation extremum、laser performance parameters and integrating performance of laser system.For measurement of low laser radiation, there are impending demands in military and civilization area. Unfortunately there is no Standard apparatus for micro-energy of laser in China which makes it impossible to establish traceability system for laser micro-energy measurement apparatus and results in non-unification of measurand. This paper studies inspection and calibration technology for laser micro-energy and establishes laser micro-energy standard which satisfies current demands for laser micro-energy metrology. The main workings made are as follows:First of all, based on laser radiation metrology technology and combining the characteristics of laser micro-energy, the inspection and calibration technology is studied. Through study of linear attenuation, laser energy is attenuated to pico-joule level which meets the requirements of laser micro-energy metrology in China. Through study of electromagnetic disturbing and random radiation shielding, reasonable shielding measures are used to avoid or depress the disturbing of various disturbing sources to ensure the accuracy of measurement.Next, through system design, laser micro-energy standard apparatus for continuous and pulsed laser are designed separately to realize automatic measurement in range of0.1pJ到10mJ. For continuous laser micro-energy standard apparatus, chopper and single pulse chooser are used to generate laser pulses, laser micro-power is measured by trapped detector and laser pulse width is measured by high speed detector and oscilloscope which enables the inspection and calibration of laser micro-energy. For pulsed laser micro-energy, wedged beam splitter is used. Through measurement of level0laser energy and attenuation ratio of beam splitter, laser micro-energy inspection and calibration is performed. The developed laser micro-energy standard apparatus are used to do research works and results are very good.In addition, to ensure reliability of measurand for laser micro-energy, the paper studies the traceability and transfer method for laser micro-energy. Aiming at different principles for continuous laser micro-energy standard and pulsed laser micro-energy standard, two different traceability methods are proposed. Continuous laser micro-energy standard apparatus is traced to cryogenic radiometer and time frequency standard while pulsed laser micro-energy standard apparatus is traced to laser micro-energy standard and optical material reflective index standard. This traceability method has solved measurand traceability problem for laser micro-energy and guarantee the unification and reliability of measurand.Finally, the paper analyzes uncertainty factors for laser micro-energy measurement in detail. Based on that analysis, different uncertainty factors are analyzed and calculated. Measurement results are assessed for uncertainty and uncertainty is given reasonably for laser micro-energy.Through studying works of this paper, metrology difficulty for laser micro-energy is solved. This working has filled up the blank in this area and facilitated the transfer workings for laser micro-energy measurand.