U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Search Publications by: Joshua Hadler (Fed)

Search Title, Abstract, Conference, Citation, Keyword or Author
Displaying 26 - 50 of 51

Progress toward Radiation-Pressure-Based Measurement of High-Power Laser Emission - Under Policy Review

October 6, 2014
Author(s)
Paul A. Williams, Joshua A. Hadler, Daniel King, Robert Lee, Frank C. Maring, Gordon A. Shaw, Nathan A. Tomlin, John H. Lehman, Marla L. Dowell
We present an overview of our efforts toward using optical radiation pressure as a means to measure optical power from high-power lasers. Early results with measurements ranging from tens of watts to 92 kW prove the concept, but validation uncertainties

Use of radiation pressure for measurement of high-power laser emission

October 15, 2013
Author(s)
Paul A. Williams, Joshua A. Hadler, Robert Lee, Frank Maring, John H. Lehman
We demonstrate a paradigm in absolute laser radiometry where a laser beam's power can be measured from its radiation pressure. Using an off-the-shelf high-accuracy mass scale and a 500 W Yb-doped fiber laser and a 92 kW CO2 laser, we show preliminary

Random testing reveals excessive power in commercial laser pointers

May 1, 2013
Author(s)
Joshua A. Hadler, Edna L. Tobares, Marla L. Dowell
In random testing of 122 commercial laser pointers, we observed that 89.7 % of green pointers and 44.4 % of red pointers were not in compliance with the Code of Federal Regulations, producing laser power in excess of the Accessible Emission Limit at one or

Accurate, inexpensive testing of handheld lasers for safe use and operation

March 7, 2013
Author(s)
Marla L. Dowell, Joshua A. Hadler
An accurate, inexpensive test bed for measurements of optical power emitted from handheld lasers is described. Our test bed consists of a thermopile detector, bandpass optical filters, an adjustable iris, and self-centering holders for mounting of the

Uncertainty calculation for spectral-responsivity measurements

September 1, 2009
Author(s)
John H. Lehman, Chih-Ming Wang, Marla L. Dowell, Joshua A. Hadler
This paper discusses a procedure for measuring the absolute spectral responsivity of optical-fiber power meters and computation of the calibration uncertainty. The procedure reconciles measurement results associated with a monochromator-based measurement

Reflective optical chopper used in NIST high-power laser measurements

November 1, 2008
Author(s)
Xiaoyu X. Li, Thomas Scott, Christopher L. Cromer, Joshua A. Hadler
For the past ten years, NIST has used high-reflectivity, optical choppers as beamsplitters and attenuators when calibrating the absolute responsivity and response linearity of detectors used with high-power CW lasers. The chopper-based technique has

High power laser calibrations at NIST

September 1, 2008
Author(s)
Xiaoyu X. Li, Joshua A. Hadler, Christopher L. Cromer, John H. Lehman, Marla L. Dowell
This document describes the calibration service for the responsivity of laser power meters and detectors used with continuous wave high power lasers at laser wavelengths of 1.06 and 10.6 micrometers. An overview of the calibration procedures, measurement

NIST optical fiber power measurements: intramural and international comparisons

October 1, 2007
Author(s)
Igor Vayshenker, John H. Lehman, David J. Livigni, Joshua A. Hadler
We discuss the results of intramural comparisons of NIST laser and optical fiber power meter (OFPM) measurements, and the results of OFPM comparisons between NIST and three National Measurement Institutes (NMIs). We also describe transfer standards

NIST Measurement Services: cw Laser Power and Energy Calibrations at NIST

July 1, 2007
Author(s)
Joshua A. Hadler, Christopher L. Cromer, John H. Lehman
This document describes a calibration service for absolute laser power and energy measurements of laser power meters and detectors used with continuous wave lasers at laser wavelengths between 325 and 1550 nm. In addition to a summary of the calibration

Broad Spectrum Capabilities for CW Laser Power Measurements at NIST

May 1, 2005
Author(s)
Joshua A. Hadler
Recent improvements for mid-level laser power measurements (1 μW to 1 W) have increased the range of calibrations available to customers of our CW laser power measurements. In this presentation we present an overview of our capabilities as well as recent

Intramural comparison of NIST laser and optical fiber power calibrations

March 1, 2004
Author(s)
John H. Lehman, Igor Vayshenker, David J. Livigni, Joshua A. Hadler
The responsivity of two optical detectors was determined by the method of direct substitution in four different NIST measurement facilities. The measurements were intended to demonstrate the determination of absolute responsivity as provided by NIST

New and Future Capabilities for CW Laser Power Measurements at NIST

January 1, 2003
Author(s)
Joshua A. Hadler
The CW Laser Radiometry project in the Optoelectronics Division at NIST is concerned with measuring steady-state laser, detector, and component properties such as laser power and energy, laser beam profile, detector spatial and angular responsivity