Micromachined Force Scale for Optical Power Measurement by Radiation Pressure Sensing

We introduce a micromachined force scale for laser power measurement by means of radiation pressure sensing. With this technique, the measured laser light is not absorbed and can be utilized while being measured. We employ silicon micromachining technology to construct a miniature force scale, opening the potential to its use for fast in-line laser process monitoring. Here, we describe the mechanical sensing principle and conversion to an electrical signal. We further outline an electrostatic force substitution process for nulling of the radiation pressure force on the sensor mirror. Finally, we look at the performance of a proof-of-concept device in open-loop operation (without the nulling electrostatic force) subjected to a modulated laser at 250 W and find its response time is less than 20 ms with noise floor dominated by electronics at 2.5 W/ $\surd $ Hz.

[1]  Uwe Brand,et al.  A new facility to realize a nanonewton force standard based on electrostatic methods , 2009 .

[2]  Thermal characterization of a cryogenic radiometer and comparison with a laser calorimeter , 1998 .

[3]  Michelle Stephens,et al.  Portable, high-accuracy, non-absorbing laser power measurement at kilowatt levels by means of radiation pressure. , 2017, Optics express.

[4]  J. Maxwell.  A Treatise on Electricity and Magnetism , 1873, Nature.

[5]  Jon R. Pratt,et al.  Milligram mass metrology using an electrostatic force balance , 2016 .

[6]  Hermann K. P. Neubert.  Instrument Transducers : An Introduction to Their Performance and Design , 1999 .

[7]  Jon R. Pratt,et al.  A self-calibrating optomechanical force sensor with femtonewton resolution , 2014, 1410.5725.

[8]  Carl Tim Kelley,et al.  Iterative methods for optimization , 1999, Frontiers in applied mathematics.

[9]  K.P.P. Pillai.  Fringing field of finite parallel-plate capacitors , 1970 .

[10]  Geometric contributions to chopper wheel optical attenuation uncertainty , 2017 .

[11]  Matthias Durr,et al.  Analysis And Design Principles Of Mems Devices , 2016 .

[12]  F. C. Fitchen,et al.  Low-Noise Electronic Design , 1973 .

[13]  J. Cook,et al.  MEASUREMENT OF LASER OUTPUT BY LIGHT PRESSURE , 1962 .

[14]  Yipeng Yuan.  A new pulse laser energy meter , 1990 .

[15]  P. Touboul,et al.  Capacitive detection scheme for space accelerometers applications , 1999 .

[16]  C. Speake,et al.  Mirror tilt immunity interferometry with a cat's eye retroreflector. , 2011, Applied optics.

[17]  Louis L. Scharf,et al.  A First Course in Electrical and Computer Engineering: With Matlab Programs and Experiments , 1990 .

[18]  J. Lehman,et al.  Noise characteristics of thermistors: Measurement methods and results of selected devices. , 2017, The Review of scientific instruments.

[19]  E D West,et al.  A Reference Calorimeter for Laser Energy Measurements. , 1972, Journal of research of the National Bureau of Standards. Section A, Physics and chemistry.

[20]  J. Lehman,et al.  Use of radiation pressure for measurement of high-power laser emission. , 2013, Optics letters.

[21]  A. L. Hugill,et al.  Limitations to the application of electrostatic feedback in gravity meters , 1986 .

[22]  K. Agatsuma,et al.  Precise measurement of laser power using an optomechanical system. , 2013, Optics express.

[23]  E. F. Nichols,et al.  The Pressure Due To Radiation , 2015 .