Introduction to the Series
Welcome to the SPIE Field Guides—a series of publications written directly for the practicing engineer or scientist. Many textbooks and professional reference books cover optical principles and techniques in depth. The aim of the SPIE Field Guides is to distill this information, providing readers with a handy desk or briefcase reference that provides basic, essential information about optical principles, techniques, or phenomena, including definitions and descriptions, key equations, illustrations, application examples, design considerations, and additional resources. A significant effort will be made to provide a consistent notation and style between volumes in the series.
Each SPIE Field Guide addresses a major field of optical science and technology. The concept of these Field Guides is a format-intensive presentation based on figures and equations supplemented by concise explanations. In most cases, this modular approach places a single topic on a page, and provides full coverage of that topic on that page. Highlights, insights, and rules of thumb are displayed in sidebars to the main text. The appendices at the end of each Field Guide provide additional information such as related material outside the main scope of the volume, key mathematical relationships, and alternative methods. While complete in their coverage, the concise presentation may not be appropriate for those new to the field.
The SPIE Field Guides are intended to be living documents. The modular page-based presentation format allows them to be updated and expanded. We are interested in your suggestions for new Field Guide topics as well as what material should be added to an individual volume to make these Field Guides more useful to you. Please contact us at fieldguides@SPIE.org.
John E. Greivenkamp, Series Editor
College of Optical Sciences
The University of Arizona
Related Field Guides
Crystal Growth, Ashok K. Batra and Mohan D. Aggarwal (Vol. FG38)
Laser Pulse Generation, Rüdiger Paschotta (Vol. FG14)
Lasers, Rüdiger Paschotta (FG12)
Nonlinear Optics, Peter E. Powers (Vol. FG29)
Probability, Random Processes, and Random Data Analysis, Larry C. Andrews and Ronald L. Phillips (Vol. FG22)
Quantum Mechanics, Brian P. Anderson (Vol. FG44)
Radiometry, Barbara G. Grant (Vol. FG23)
Solid State Physics, Marek Wartak and Ching-Yao Fong (Vol. FG43)
Spectroscopy, David W. Ball (Vol. FG08)
How to Set Up a Laser Lab, Ken L. Barat (Vol. SL02)
Laser Beam Quality Metrics, T. Sean Ross (Vol. TT96)
Laser Plasma Physics: Forces and the Nonlinearity Principle, Heinrich Hora (Vol. PM250)
Laser Safety in the Lab, Ken L. Barat (Vol. PM212)
Laser Systems Engineering, Keith J. Kasunic (Vol. PM271)
Solid State Lasers: Tunable Sources and Passive Q-Switching Elements, Yehoshua Y. Kalisky (Vol. PM243)
The Physics and Engineering of Solid State Lasers, Yehoshua Y. Kalisky (Vol. TT71)
Powering Laser Diode Systems, Grigoriy A. Trestman (Vol. TT112)
Table of Contents
Preface
Cooling or refrigeration is based on heat removal and dates back thousands of years to when people tried to preserve their food using ice and snow. The laser—a groundbreaking scientific achievement of the 20th century— has revolutionized the cooling process. The advent of lasers brought laser cooling, also known as optical refrigeration, into existence. Today, laser cooling and its applications represent one of the major subfields of atomic, molecular, and solid state physics.
This Field Guide provides an overview of the basic principles of laser cooling of atoms, ions, nanoparticles, and solids, including Doppler cooling, polarization gradient cooling, different sub-recoil schemes of laser cooling, forced evaporation, laser cooling with anti-Stokes fluorescence, hybrid laser cooling, and Raman and Brillouin cooling. It also covers radiation-balanced lasers and Raman lasers with heat mitigation, and considers the basic principles of optical dipole traps, magnetic traps, and magneto-optical traps. This Field Guide will serve both to introduce students, scientists, and engineers to this exciting field, and to provide a quick reference guide for the essential math and science.
I would like to thank SPIE Press Manager Timothy Lamkins and Series Editor John Greivenkamp for the opportunity to write a Field Guide for one of the most interesting areas of photonics, as well as SPIE Press Sr. Editor Dara Burrows for her help.
This book is dedicated to my mom, Albina.
Galina Nemova
September 2019
Glossary
Fundamental constants
μ B = 9.27400899 × 10−24 (J·T−1) | Bohr magneton |
kB = 1.3806503 × 10−23 (J·K−1) | Boltzmann constant |
ɛ0 = 8.854187817 × 10−12 (F·m−1) | vacuum permittivity or electric constant |
me = 9.10938188 × 10−31 (kg) | electron mass |
gs = 2.0023193043737 | electron spin g-factor |
e = 1.6021766208 × 10−19(C) | elementary charge |
α = 7.297352533 × 10−3 | fine structure constant |
μ0 = 4π × 10−7 (H·m−1) | permeability of vacuum |
h = 6.62606876 × 10−34 (J·s) | Planck’s constant |
ħ = h/2π = 1.054571596×10−34 (J·s) | reduced Planck’s constant |
c = 299792458 (m·s−1) | speed of light in vacuum |
σ = 5.67 × 10−8 (Wm−2K−4) | Stefan–Boltzmann constant |
Glossary of Symbols and Acronyms
ρ
density operator
σ a
absorption cross section
σ e
emission cross section
ψ
wave function
ω
angular frequency
B
magnetic field
E
electric field
EF
Fermi energy
gF
Landé g-factor
gl
electron orbital g-factor
gs
electron spin g-factor
k
wave vector
kr
restoring-force constant
t
time
T
temperature
v
velocity
vs
speed of sound
Quantum mechanical symbols
d
atomic dipole moment
F
total angular momentum quantum number (used by spectroscopists for atoms with an odd isotope number)
F
total angular momentum (for atoms with an odd isotope number)
magnitude of the total angular momentum F
I
nuclear spin angular momentum
j
total angular momentum quantum number (for a single particle)
J
total angular momentum quantum number (used by spectroscopists for atoms with an even isotope number)
J
total angular momentum (for atoms with an even isotope number)
magnitude of the total angular momentum J
l
orbital angular momentum quantum number or orbital quantum number (for a single particle)
L
orbital angular momentum quantum number (for a system of several particles)
L
orbital angular momentum (for a system of several particles)
magnitude of the orbital angular momentum L
ml
magnetic quantum number
n
principal quantum number (for a single particle)
s
spin quantum number (for a single particle)
S
spin quantum number (for a system of several particles)
S
spin angular momentum (for a system of several particles)
magnitude of the spin angular momentum S
Acronyms and Abbreviations
AC
alternating current
ASF
anti-Stokes fluorescence
BEC
Bose–Einstein condensate
BYF
BaY2F8
CARS
coherent anti-Stokes Raman scattering
CG
Clebsch–Gordan (coefficient)
CNBZn
CdF2-CdCl2-NaF-BaF2-BaCl2-ZnF2
DC
direct current
ED
electrical dipole
EIT
electromagnetically induced transparency
EM
electromagnetic
ESA
excited-state absorption
EQ
electric quadrupole
f-factor
oscillator strength
FMHM
full width at half maximum
GEF
geometrical efficiency factor
IPTS
International Practical Temperature Scale
KPC
KPb2Cl5
LD
Lamb–Dicke (regime)
LO
longitudinal optical
MAT
minimum achievable temperature
MD
magnetic dipole
MOT
magneto-optical trap
ODT
optical dipole trap
PSD
phase-space density
QM
quantum model
RE
rare earth
RF
radiofrequency
rms
root-mean-square
RWA
rotating-wave approximation
SCM
semi-classical model
SHG
second harmonic generation
SLT
second law of thermodynamics
SNR
signal-to-noise ratio
SRAP
stimulated Raman adiabatic passage
SRE
selective resonant enhancement
SSRS
stimulated Stokes Raman scattering
STIRAP
stimulated Raman adiabatic passage
TA
transverse acoustic
TIR
total internal reflection
TO
transverse optical
TOF
time-of-flight
TOP
time-orbiting potential
VECSEL
vertical-external-cavity surface-emitting laser
VSCPT
velocity-selective coherent population trapping
VUV
vacuum ultraviolet
YAG
Y3Al5O12 (yttrium aluminium garnet)
YLF
YLiF4 (yttrium lithium fluoride)
ZBLAN
ZrF4-BaF2-LaF3-AlF3-NaF
ZBLANP
ZrF4-BaF2-LaF3-AlF3-NaF-PbF3 (heavy-metal fluoride glass)