II BRL
Belford Research Limited
LASER DAMAGE
Continuing our CW laser damage research to include substrate expansion coefficients as a marker for threshold influence, especially materials renowned for their low expansion properties. We tested identical coatings on these and a number of low softenining-point substrates.
CW damage is classically governed by a total dosage/time mechanism determining the power levels at which steady-state equilibria are obtained. Despite this, true damage occurred in scan tests. Scanning is not the recommended test procedure adopted for CW, as a steady state is unable to be established. CW use does not involve a moving target. However, new applications can see surface features giving rise to damage when scanning is used. These events are scanning-induced and happen even when the coating threshold is far higher when tested classically.
As an extension to last year's research program, an investigation in radiation induced contaminants has been ongoing and found to not only be power sensitive but also total energy related.
Our new custom-built, increased power, 1535 nm Laser allows testing to be extended to higher power levels whilst still keeping our minimum spot size to >235 µm.
Testing at 1 µm can be used, with corrections to obtain approximate 2 µm results. Laser damage testing at 2 µm is inaccurate due to a plethora of problems associated with 2 µm sensors and beam diagnostics. However, as more test houses adopt this methodology failures in the end product testing are becoming common. Auxiliary test procedures were examined and remedies explored.
BRL has increased test capacity with a new powerful 1064 nm Laser and upconverters allowing both test and research activities at extended wavelengths.
This month's edition of Electro Optics Magazine features an article on the test ethos of BRL and our latest whitepaper on threshold elevation. Gemma Church explains how and why BRL takes a robust and accurate approach to laser damage testing, alongside comments from our CEO Dr Rona Belford on the potential to overtest samples during a laser damage test.
BRL's latest whitepaper expands on the subject of annealing and its influence on accurate determination of laser damage threshold. This whitepaper addresses the threshold elevation that can arise from over dosing the test sample with laser light.The whitepaper can be found here.
We are pleased to welcome Andrew Ritchie as a Physicist and Systems Programmer. Andrew's experience in A.I and robotics will be used to address a high level of system integration at BRL, enhancing the efficacy of our knowledgeable team of laser damage test experts.
BRL presents "Laser Damage for Optical Coaters" via the Digital Exhibition at SPIE Security + Defence 2020. This virtual demonstration shows real time optical samples under test and explains what samples are needed for different types of testing. Exciting live footage of laser damage is presented. It is now available to view on the SPIE website.
This month's Electro Optics Viewpoint presents a short profile of BRL's capabilities as a laser damage test house and highlights the requirement of high LIDT for high power lasers. This Viewpoint, authored by BRL's CEO Dr Rona Belford, also examines the distinct regimes of laser damage and how they pertain to pulsed, CW or ultrafast laser systems.
This month's Electro Optics magazine features BRL's latest whitepaper, "High Power Laser Damage & Annealing - Justification for ISO Standard Recommendations" by Dr Rona Belford and Kieran R Ross. The potential for large scale variance in LIDT values is explained. This article emphaises critical details in the ISO standards. It is now available on the Electro Optics website.
BRL has released a new whitepaper detailing the effects of small parameter changes, deviating from ISO standard laser damage testing. These small changes give rise to inacurate elevation of threshold values due to the test material changing (annealing) during the test. The importance of low dosage testing is verified. The whitepaper can be found here.
Electro Optics Magazine has issued an article by Andy Extance as part of a Tech Focus on Laser Optics. "Coating Techniques Push Laser Component Limits" discussing advances in coating technology and highlighting BRL as a state of the art laser damage test house. The article can also be found here.
Our recent whitepaper on CW Laser Damage is free to read via the June digital issue of Electro Optics Magazine.
This month's Electro Optics magazine features BRL's latest whitepaper. The whitepaper, "High Power Pulsed and CW Laser Damage, Understanding the differences in Pulsed and CW damage" by Dr Rona Belford, Kieran R Ross and Dr Matthew Duff, details and contrasts pulsed and CW laser damage mechanisms, as well as presenting LIDT results for optical substrates. It is available on the Electro Optics website.
BRL has released a video targeted at optical coaters. We explain what the coater needs to provide in terms of data and sample. We also show videos of both pulsed and CW damage. The demo was originally compiled for the exhibitors showcase at SPIE Photonics Europe 2020. The video can be found here.
BRL has released a whitepaper, detailing and contrasting the differences in Pulsed and CW laser damage. We also dispel some of the common misunderstandings relating to CW Laser Damage and its units. This work was funded by Leonardo Edinburgh, Gooch and Housego Precision Optics and BRL Laser Damage. The whitepaper can be found here.
BRL now offers continuous wave (CW) laser damage testing up to a linear power density of 500 kW/cm. This linear power density will cover more than 95% of the CW market.
We are pleased to welcome Dr Matthew Duff to our team. Matthew has expertise in Ultra-Fast High Power lasers. He fills a new position at BRL.
We are pleased to welcome Kieran Ross to our research team. He will be our Lead Physicist, specialising in optical assemblies.
Arran Fernie has taken up a new position at BRL as a Laser Physicist.
We are featured in an article published by Electro Optics. "Coating techniques push laser component limits" by Andy Extance, discusses the current advances in coating technology and the importance of laser damage testing. It is available on the Electro Optics website.
BRL co-authored a whitepaper on laser damage in high-power optics with Gooch and Housego. It is available on the Gooch and Housego website. The paper showcases our recent Laser Damage Live videos, which you can find on our media page.
We have just begun a series of videos on live laser damage. These show unusual and dramatic damage events recorded in our labs. Watch it on our media page.
Our senior Research Physicist, Dr Mulholland gave an invited talk on laser damage testing. He gave examples of BRL's work with the Kerr Effect and showcased two new videos taken of live damage events.
BRL successfully completed the SMART feasibility project on 2-micron laser damage testing. The project was successful and BRL are taking their concepts a stage further. Much work is still required to gain confidence in the procedures investigated.
BRL exhibited and Dr. R E Belford gave the demo talk Laser Damage Basics.
Dr Kieran Mulholland joined our group full time. He has a PhD in experimental nuclear physics and has previous experience of laser damage techniques.
Sean is responsible for the extensive electronic and sensing equipment in our firing labs.
BRL commenced a one-year SMART feasibility project. Laser damage at 2 microns presents limiting difficulties which make the test both expensive and challenging to execute. This research project approached the problem from a materials based viewpoint and proposed a novel method for performing laser damage testing at 2 microns using an alternative methodology.
Dr Belford presented the invited talk entitled "Laser Damage on optical components".
Multi-wavelength laser damage test bed became active due to the completion of a Scottish Enterprise feasibility project.