Laser Safety: Practical Knowledge and Solutions

220 Pages·2019·45.107 MB·English

by  Ken Barat

Laser Safety
Practical knowledge and solutions
IOP Series in Coherent Sources and Applications
About the Editor
FJDuarteisalaserphysicistbasedinWesternNewYork,USA.Hehasa30+year
experienceintheacademic,industrialanddefensesectors.Duarteiseditor/authorof
13 laser optics books and sole author of two books (Tunable Laser Optics and
Quantum Optics for Engineers). He has made original contributions to the field of
narrow-linewidth tunable laser oscillators, organic laser gain media, nanoparticle
solid-state laser materials, and laser interferometry. He is also the author of the
multiple-prism grating dispersion theory applicable to tunable lasers, laser pulse
compression, and coherent microscopy. Duarte is a Fellow of the Australian
Institute of Physics (1987) and a Fellow of the Optical Society of America (1993).
He has been awarded the Paul F Foreman Engineering Excellence Award and the
David Richardson Medal from the Optical Society.
Coherent Sources and Applications
Since the discovery of the laser, applications of this wondrous emitter of coherent
radiationhavegrownenormously.Subsequently,wehavealsobecomefamiliarwith
additional sources of coherent radiation such as the free electron laser, optical
parametricoscillators,andinterferometricemitters.Theaimofthisnewbookseries
is to explore and explain the physics and technology of widely applied sources of
coherent radiation and to match them with utilitarian and cutting-edge scientific
applications.Selectedcoherent sourcesarethose thatofferadvantagesinparticular
emissioncharacteristicsareassuchasbroadtunability,highspectralcoherence,high
energy, or high power. An additional area of inclusion is those coherent sources
capable of high performance in the miniaturized realm. Selected uses include
practical applications valuable to the industrial, commercial, and medical sectors.
Particularattentionwillbegiventoscientificapplicationswithabrightfuturescope
such as coherent (or laser) spectroscopy, astronomy, biophotonics, space commu-
nications, space interferometry, and quantum entanglement.
Publishing benefits
Authors are encouraged to take advantage of the features made possible by
electronic publication to enhance the reader experience through the use of colour,
animation and video, and incorporating supplementary files in their work.
Do you have an idea of a book that you’d like to explore?
For further information and details of submitting book proposals, see iopscience.
org/books or contact Ashley Gasque at [email protected].
Laser Safety
Practical knowledge and solutions
Ken Barat
42179 W. Santa Fe St, Maricopa, Arizona, AZ 85138, USA
IOP Publishing, Bristol, UK
ªIOPPublishingLtd2019
Allrightsreserved.Nopartofthispublicationmaybereproduced,storedinaretrievalsystem
ortransmittedinanyformorbyanymeans,electronic,mechanical,photocopying,recording
orotherwise,withoutthepriorpermissionofthepublisher,orasexpresslypermittedbylawor
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accordancewiththetermsoflicencesissuedbytheCopyrightLicensingAgency,theCopyright
ClearanceCentreandotherreproductionrightsorganizations.
PermissiontomakeuseofIOPPublishingcontentotherthanassetoutabovemaybesought
[email protected].
KenBarathasassertedhisrighttobeidentifiedastheauthorofthisworkinaccordancewith
sections77and78oftheCopyright,DesignsandPatentsAct1988.
ISBN 978-0-7503-1692-7(ebook)
ISBN 978-0-7503-1690-3(print)
ISBN 978-0-7503-1691-0(mobi)
DOI 10.1088/2053-2563/ab0f25
Version:20190601
IOPExpandingPhysics
ISSN2053-2563(online)
ISSN2054-7315(print)
BritishLibraryCataloguing-in-PublicationData:Acataloguerecordforthisbookisavailable
fromtheBritishLibrary.
PublishedbyIOPPublishing,whollyownedbyTheInstituteofPhysics,London
IOPPublishing,TempleCircus,TempleWay,Bristol,BS16HG,UK
USOffice:IOPPublishing,Inc.,190NorthIndependenceMallWest,Suite601,Philadelphia,
PA19106,USA
The contributing authors are what make this text stand out from other texts on laser
safety. It is to them that I owe the greatest gratitude. I must also include by grand-
daughter Margo, who never fails to bring a smile to my face. In today’s world that is
priceless. Hello Margo, it is Grandpops.

Contents
Preface xviii
Editor biography xix
List of contributors xx
Part I The basics of laser safety
1 Why are laser accidents still happening? 1-1
1.1 Bad behavior and no negative consequences 1-1
1.2 Possible future: virtual reality 1-4
1.3 On the job training/mentoring (a topic you will find mentioned 1-4
several times in this text, but learning is through repetition)
1.4 Recommendation 1-5
1.5 Trainer, what are your responsibilities? 1-5
1.6 Trainee, what are your responsibilities? 1-5
1.7 What makes good coaching? 1-6
1.8 Training review 1-6
2 Classification: a means of hazard communication 2-1
2.1 Introduction 2-1
2.2 KEY ITEM about laser hazard classification and why people care 2-1
2.3 Terms to know 2-2
2.4 Explanation of individual laser classes 2-2
2.5 System classification 2-2
2.5.1 Class 1—CDRH 2-4
2.5.2 Class 1M 2-4
2.5.3 IEC Class 1C 2-5
2.5.4 Class 2—CDRH 2-5
2.5.5 Class 2M 2-6
2.5.6 Class 3R—CDRH 2-6
2.5.7 Class 3R 2-6
2.5.8 Class 4 CDRH 2-7
2.6 Classification changes that are being discussed 2-7
2.6.1 Class 5 2-7
vii
LaserSafety
2.6.2 Classification based on control measures—laser control groups 2-8
2.7 Training slides on classification 2-8
3 Biological effects: something you should know about 3-1
3.1 Confession time 3-1
3.2 Let’s be truthful 3-1
3.3 Oh! I forgot about that 3-1
3.4 What is all the concern over? 3-2
3.5 All aboard—train station analogy 3-2
3.6 Injury below damage threshold 3-3
3.7 Indoor problems below the MPE do exist 3-3
3.8 Equipment damage 3-4
3.9 So where do wavelengths go? 3-4
3.9.1 UV 3-4
3.9.2 Visible 3-4
3.9.3 Near-infrared 700 nm–1400 nm 3-5
3.9.4 Mid- and far-IR 3-5
3.10 How is damage caused? 3-5
3.11 The anatomy of your eye 3-6
3.11.1 The cornea 3-6
3.11.2 The aqueous chambers 3-6
3.11.3 The lens 3-6
3.11.4 The retina 3-6
3.11.5 The iris/pupil 3-7
3.12 800 nm trap 3-7
3.12.1 Damage mechanisms by wavelength 3-8
3.13 Things to know 3-8
3.13.1 Aversion response 3-8
3.13.2 Near IR effects 3-8
3.13.3 Injuries outside the fovea 3-8
3.13.4 Vitreal hemorrhages 3-9
3.13.5 Blood in the eye, toxic effects 3-9
3.13.6 Beam size does have an effect 3-9
3.13.7 Damn! corneal injury hurts 3-10
3.14 Physiological damage mechanisms 3-10
3.15 Quick summary 3-10
3.16 Skin 3-10
3.17 Conclusion 3-11
viii
LaserSafety
4 Laser safety terms: the language LSOs speak 4-1
4.1 Introduction 4-1
4.2 Glossary of terms 4-1
5 Risk assessment for lasers 5-1
5.1 Purpose 5-1
5.2 Applicability 5-1
5.3 Preface 5-1
5.4 Background 5-2
5.5 What is a risk assessment? 5-3
5.6 Fundamental concepts 5-3
5.7 Terms and definitions 5-4
5.8 Likelihood of occurrence (probability) 5-5
5.9 Consequence (severity) 5-5
5.10 Why is risk assessment important? 5-5
5.11 Where are risk assessments noted/required by regulations? 5-6
5.12 What is the goal of risk assessment? 5-7
5.13 What is acceptable risk? 5-7
5.14 Note on structure of the risk assessment worksheets 5-10
6 Laser protective eyewear, looking sharp in the laser lab 6-1
6.1 Introduction 6-1
6.2 Eyewear labeling 6-2
6.2.1 What does > or + mean? 6-2
6.3 Can eyewear break down/fail? 6-2
6.4 Ultrafast pulses and laser eyewear 6-4
6.5 Angle of exposure 6-5
6.6 Attacked from behind 6-5
6.7 Unusual eyewear event # 1 6-5
6.8 Unusual eyewear event # 2 6-6
6.9 Absorptive versus reflective filter 6-6
6.10 Impact resistance 6-6
6.11 Manufacturer protection curves and non-labelled wavelengths 6-7
6.12 What to do if labeling wears off? 6-7
6.13 Prescription eyewear 6-7
6.14 Alignment eyewear 6-7
ix