Diode Laser for Acne

7/27/2019 Diode Laser for Acne

1/9

DIODE LASER FOR ACNE

The diode laser is a non ablative laser that is designed specifically to target the root case of

acne! the sebaceos gland" It provides a perfect balance of controlled cooling of the epider#is$ith precise heating of the pper der#is that #ini#i%es disco#fort" Dring the laser treat#ent! a

laser penetrates the pper layers of the s&in only! sti#lating ne$ collagen deposition andtargeting da#age $here it is #ost prevalent"

The diode lasers $avelength targets and heats $ater in the s&ins pper der#is! inclding a #ild

ther#al in'ry to collagen" Fro# this in'ry!the body(s natral healing process initiates the

deposition of ne$ organi%ed collagen" As the ne$ collagen for#s! it helps s#oothen and fill inacne scars and redce the n#ber of acne lesions visible on the s&in"

It(s a non)invasive $ay to treat acne and redce the appearance of acne scars" Non)invasive

lasers do not ct or re#ove the s&in srface* instead their action occrs nderneath the oter

layers of the s&in" +ecase it does not re#ove any s&in fro# the srface of yor face dring

treat#ent! it is a gentle procedre that re,ires little or no do$nti#e"

Laser diode treat#ent is not very painfl! bt to help yo to control and disco#fort or pain!

analgesics are applied to the s&in before treat#ent starts" Side effects #ay inclde te#porary

redness and s$elling of the treated areas"

It can be perfor#ed on all s&in types and $or&s $ell at redcing acne and i#proving the loo& of

acne scars" -hile yo #ay notice significant i#prove#ent after the first treat#ent! it sally

ta&es . or / treat#ents to see the fll reslts"

In a recent stdy sing the diode laser! every patient sa$ a significant redction in acne lesions"

After one treat#ent! lesion conts decreased by .01" A 231 decrease $as seen after t$otreat#ents! and lesion conts decreased by 3.1 $ith a third treat#ent"

What is Diode Laser ?

A laser diode is electrically a4)i)n diode"The active region of the laser diode is in the intrinsic5I6 region! and the carriers! electrons and holes! are p#ped into it fro# the N and 4 regions

respectively" -hile initial diode laser research $as condcted on si#ple 4)N diodes! all #odern

lasers se the doble)heterostrctre i#ple#entation! $here the carriers and the photons are

confined in order to #a7i#i%e their chances for reco#bination and light generation" 8nli&e areglar diode sed in electronics! the goal for a laser diode is that all carriers reco#bine in the I

region! and prodce light" Ths! laser diodes are fabricated sing direct bandgap se#icondctors"

The laser diode epita7ial strctre is gro$n sing one of the crystal gro$th techni,es! sallystarting fro# an N doped sbstrate! and gro$ing the I doped active layer! follo$ed by the 4

doped cladding! and a contact layer" The active layer #ost often consists of ,ant# $ells!

$hich provide lo$er threshold crrent and higher efficiency" 9:;
http://www.acne-lasertreatment.net/types_acne_scars.htmlhttp://en.wikipedia.org/wiki/P-i-n_diodehttp://en.wikipedia.org/wiki/P-i-n_diodehttp://en.wikipedia.org/wiki/P-i-n_diodehttp://en.wikipedia.org/wiki/Laser_diode#cite_note-1http://www.acne-lasertreatment.net/types_acne_scars.htmlhttp://en.wikipedia.org/wiki/P-i-n_diodehttp://en.wikipedia.org/wiki/Laser_diode#cite_note-1


2/9

Laser diodes for# a sbset of the larger classification of se#icondctorp)n'nction diodes"

For$ard electrical bias across the laser diode cases the t$o species ofcharge carrier< holesand

electrons< to be =in'ected= fro# opposite sides of thep)n'nction into the depletion region">oles are in'ected fro# thep)doped! and electrons fro# the n)doped! se#icondctor" 5A

depletion region!devoid of any charge carriers! for#s as a reslt of the difference in electrical

potential bet$een n) andp)type se#icondctors $herever they are in physical contact"6 De tothe se of charge in'ection in po$ering #ost diode lasers! this class of lasers is so#eti#es

ter#ed =in'ection lasers!= or =in'ection laser diode= 5ILD6" As diode lasers are se#icondctor

devices! they #ay also be classified as se#icondctor lasers" Either designation distingishesdiode lasers fro# solid)state lasers"

Another #ethod of po$ering so#e diode lasers is the se of optical p#ping" Optically p#ped

se#icondctor lasers 5O4SL6 se a III)? se#icondctor chip as the gain #edi#! and another

laser 5often another diode laser6 as the p#p sorce" O4SL offer several advantages over ILDs!particlarly in $avelength selection and lac& of interference fro# internal electrode strctres"9@;

9.;

-hen an electron and a hole are present in the sa#e region! they #ay reco#bineor =annihilate=

$ith the reslt being spontaneos e#ission i"e"! the electron #ay re)occpy the energy state ofthe hole! e#itting a photon $ith energy e,al to the difference bet$een the electron and hole

states involved" 5In a conventional se#icondctor 'nction diode! the energy released fro# the

reco#bination of electrons and holes is carried a$ay asphonons! i"e"! lattice vibrations! ratherthan as photons"6 Spontaneos e#ission gives the laser diode belo$ lasing thresholdsi#ilar

properties to an LED" Spontaneos e#ission is necessary to initiate laser oscillation! bt it is one

a#ong several sorces of inefficiency once the laser is oscillating"

The difference bet$een the photon)e#itting se#icondctor laser and conventional phonon)

e#itting 5non)light)e#itting6 se#icondctor 'nction diodes lies in the se of a different type ofse#icondctor! one $hose physical and ato#ic strctre confers the possibility for photon

e#ission" These photon)e#itting se#icondctors are the so)called=direct bandgap=se#icondctors" The properties of silicon and ger#ani#! $hich are single)ele#ent

se#icondctors! have bandgaps that do not align in the $ay needed to allo$ photon e#ission and

are not considered =direct"= Other #aterials! the so)called co#pond se#icondctors! have

virtally identical crystalline strctres as silicon or ger#ani# bt se alternating arrange#entsof t$o different ato#ic species in a chec&erboard)li&e pattern to brea& the sy##etry" The

transition bet$een the #aterials in the alternating pattern creates the critical =direct bandgap=

property" Balli# arsenide! indi# phosphide!galli# anti#onide! and galli# nitrideare alle7a#ples of co#pond se#icondctor #aterials that can be sed to create 'nction diodes that

e#it light"

In the absence of sti#lated e#ission 5e"g"! lasing6 conditions! electrons and holes #ay coe7ist in

pro7i#ity to one another! $ithot reco#bining! for a certain ti#e! ter#ed the =pper)statelifeti#e= or =reco#bination ti#e= 5abot a nanosecond for typical diode laser #aterials6! before

they reco#bine" Then a nearby photon $ith energy e,al to the reco#bination energy can case

reco#bination by sti#lated e#ission" This generates another photon of the sa#e fre,ency!travelling in the sa#e direction! $ith the sa#epolari%ationandphaseas the first photon" This
http://en.wikipedia.org/wiki/Charge_carrierhttp://en.wikipedia.org/wiki/Charge_carrierhttp://en.wikipedia.org/wiki/Electron_holehttp://en.wikipedia.org/wiki/Electronhttp://en.wikipedia.org/wiki/Electronhttp://en.wikipedia.org/wiki/Depletion_zonehttp://en.wikipedia.org/wiki/Depletion_zonehttp://en.wikipedia.org/wiki/Solid-state_laserhttp://en.wikipedia.org/wiki/Laser_diode#cite_note-2http://en.wikipedia.org/wiki/Laser_diode#cite_note-3http://en.wikipedia.org/wiki/Recombination_(physics)http://en.wikipedia.org/wiki/Spontaneous_emissionhttp://en.wikipedia.org/wiki/Spontaneous_emissionhttp://en.wikipedia.org/wiki/Phononhttp://en.wikipedia.org/wiki/Lasing_thresholdhttp://en.wikipedia.org/wiki/Light-emitting_diodehttp://en.wikipedia.org/wiki/Direct_and_indirect_band_gapshttp://en.wikipedia.org/wiki/Direct_and_indirect_band_gapshttp://en.wikipedia.org/wiki/Direct_and_indirect_band_gapshttp://en.wikipedia.org/wiki/Direct_bandgaphttp://en.wikipedia.org/wiki/Gallium_arsenidehttp://en.wikipedia.org/wiki/Indium_phosphidehttp://en.wikipedia.org/wiki/Indium_phosphidehttp://en.wikipedia.org/wiki/Gallium_antimonidehttp://en.wikipedia.org/wiki/Gallium_nitridehttp://en.wikipedia.org/wiki/Gallium_nitridehttp://en.wikipedia.org/wiki/Stimulated_emissionhttp://en.wikipedia.org/wiki/Polarization_(waves)http://en.wikipedia.org/wiki/Polarization_(waves)http://en.wikipedia.org/wiki/Phase_(waves)http://en.wikipedia.org/wiki/Phase_(waves)http://en.wikipedia.org/wiki/Charge_carrierhttp://en.wikipedia.org/wiki/Electron_holehttp://en.wikipedia.org/wiki/Electronhttp://en.wikipedia.org/wiki/Depletion_zonehttp://en.wikipedia.org/wiki/Solid-state_laserhttp://en.wikipedia.org/wiki/Laser_diode#cite_note-2http://en.wikipedia.org/wiki/Laser_diode#cite_note-3http://en.wikipedia.org/wiki/Recombination_(physics)http://en.wikipedia.org/wiki/Spontaneous_emissionhttp://en.wikipedia.org/wiki/Phononhttp://en.wikipedia.org/wiki/Lasing_thresholdhttp://en.wikipedia.org/wiki/Light-emitting_diodehttp://en.wikipedia.org/wiki/Direct_and_indirect_band_gapshttp://en.wikipedia.org/wiki/Direct_bandgaphttp://en.wikipedia.org/wiki/Gallium_arsenidehttp://en.wikipedia.org/wiki/Indium_phosphidehttp://en.wikipedia.org/wiki/Gallium_antimonidehttp://en.wikipedia.org/wiki/Gallium_nitridehttp://en.wikipedia.org/wiki/Stimulated_emissionhttp://en.wikipedia.org/wiki/Polarization_(waves)http://en.wikipedia.org/wiki/Phase_(waves)


3/9

#eans that sti#lated e#ission cases gain in an optical $ave 5of the correct $avelength6 in the

in'ection region! and the gain increases as the n#ber of electrons and holes in'ected across the

'nction increases" The spontaneos and sti#lated e#ission processes are vastly #ore efficientin direct bandgapse#icondctors than inindirect bandgapse#icondctors* therefore siliconis

not a co##on #aterial for laser diodes"

As in other lasers! the gain region is srronded $ith an optical cavityto for# a laser" In the

si#plest for# of laser diode! an optical $avegide is #ade on that crystal srface! sch that thelight is confined to a relatively narro$ line" The t$o ends of the crystal are cleaved to for#

perfectly s#ooth! parallel edges! for#ing a Fabry


4/9

Type of Diode Laser

The si#ple laser diode strctre! described above! is e7tre#ely inefficient" Sch devices re,ire

so #ch po$er that they can only achieve plsed operation $ithot da#age" Althoghhistorically i#portant and easy to e7plain! sch devices are not practical"

Double heterostructure lasers

Diagra# of front vie$ of a doble heterostrctre laser diode* not to scale

In these devices! a layer of lo$bandgap#aterial is sand$iched bet$een t$o high bandgap

layers" One co##only)sed pair of #aterials isgalli# arsenide5BaAs6 $ith al#ini# galli#

arsenide5Al7Ba5:)76As6" Each of the 'nctions bet$een different bandgap #aterials is called a

heterostructure! hence the na#e =doble heterostrctre laser= orDHlaser" The &ind of laser

diode described in the first part of the article #ay be referred to as a homojunctionlaser! forcontrast $ith these #ore poplar devices"

The advantage of a D> laser is that the region $here free electrons and holes e7ist

si#ltaneoslythe active regionis confined to the thin #iddle layer" This #eans that #any#ore of the electron)hole pairs can contribte to a#plificationnot so #any are left ot in the

poorly a#plifying periphery" In addition! light is reflected fro# the hetero'nction* hence! the

light is confined to the region $here the a#plification ta&es place"
http://en.wikipedia.org/wiki/Bandgaphttp://en.wikipedia.org/wiki/Gallium_arsenidehttp://en.wikipedia.org/wiki/Gallium_arsenidehttp://en.wikipedia.org/wiki/Gallium_arsenidehttp://en.wikipedia.org/wiki/Aluminium_gallium_arsenidehttp://en.wikipedia.org/wiki/Aluminium_gallium_arsenidehttp://en.wikipedia.org/wiki/Heterostructurehttp://en.wikipedia.org/wiki/Active_laser_mediumhttp://en.wikipedia.org/wiki/File:Simple_dh_laser_diode.svghttp://en.wikipedia.org/wiki/File:Simple_dh_laser_diode.svghttp://en.wikipedia.org/wiki/Bandgaphttp://en.wikipedia.org/wiki/Gallium_arsenidehttp://en.wikipedia.org/wiki/Aluminium_gallium_arsenidehttp://en.wikipedia.org/wiki/Aluminium_gallium_arsenidehttp://en.wikipedia.org/wiki/Heterostructurehttp://en.wikipedia.org/wiki/Active_laser_medium


5/9

Quantum well lasers

Diagra# of front vie$ of a si#ple ,ant# $ell laser diode* not to scale

If the #iddle layer is #ade thin enogh! it acts as a,ant# $ell"This #eans that the vertical

variation of the electrons $avefnction! and ths a co#ponent of its energy! is ,anti%ed" The

efficiency of a ,ant# $ell laseris greater than that of a bl& laser becase thedensity of statesfnction of electrons in the ,ant# $ell syste# has an abrpt edge that concentrates electrons

in energy states that contribte to laser action"

Lasers containing #ore than one ,ant# $ell layer are &no$n as multiple quantum welllasers"ltiple ,ant# $ells i#prove the overlap of the gain region $ith the optical $avegide#ode"

Frther i#prove#ents in the laser efficiency have also been de#onstrated by redcing the

,ant# $ell layer to a ,ant# $ireor to a =sea= of ,ant# dots"

Quantum cascade lasers

ain articleG Hant# cascade laser

In a ,ant# cascade laser!the difference bet$een ,ant# $ell energy levels is sed for thelaser transition instead of the bandgap" This enables laser action at relatively long $avelengths!

$hich can be tned si#ply by altering the thic&ness of the layer" They are hetero'nction lasers"

Separate confinement heterostructure lasers

Diagra# of front vie$ of a separate confine#ent heterostrctre ,ant# $ell laser diode* not to

scale
http://en.wikipedia.org/wiki/Quantum_wellhttp://en.wikipedia.org/wiki/Quantum_wellhttp://en.wikipedia.org/wiki/Quantum_wellhttp://en.wikipedia.org/wiki/Wavefunctionhttp://en.wikipedia.org/wiki/Quantum_well_laserhttp://en.wikipedia.org/wiki/Density_of_stateshttp://en.wikipedia.org/wiki/Density_of_stateshttp://en.wikipedia.org/wiki/Waveguidehttp://en.wikipedia.org/wiki/Normal_modehttp://en.wikipedia.org/wiki/Quantum_wirehttp://en.wikipedia.org/wiki/Quantum_dothttp://en.wikipedia.org/wiki/Quantum_cascade_laserhttp://en.wikipedia.org/wiki/Quantum_cascade_laserhttp://en.wikipedia.org/wiki/Quantum_cascade_laserhttp://en.wikipedia.org/wiki/Wavelengthhttp://en.wikipedia.org/wiki/File:Simple_sch_laser_diode.svghttp://en.wikipedia.org/wiki/File:Simple_sch_laser_diode.svghttp://en.wikipedia.org/wiki/File:Simple_qw_laser_diode.svghttp://en.wikipedia.org/wiki/File:Simple_qw_laser_diode.svghttp://en.wikipedia.org/wiki/Quantum_wellhttp://en.wikipedia.org/wiki/Wavefunctionhttp://en.wikipedia.org/wiki/Quantum_well_laserhttp://en.wikipedia.org/wiki/Density_of_stateshttp://en.wikipedia.org/wiki/Waveguidehttp://en.wikipedia.org/wiki/Normal_modehttp://en.wikipedia.org/wiki/Quantum_wirehttp://en.wikipedia.org/wiki/Quantum_dothttp://en.wikipedia.org/wiki/Quantum_cascade_laserhttp://en.wikipedia.org/wiki/Quantum_cascade_laserhttp://en.wikipedia.org/wiki/Wavelength


6/9

The proble# $ith the si#ple ,ant# $ell diode described above is that the thin layer is si#ply

too s#all to effectively confine the light" To co#pensate! another t$o layers are added on!

otside the first three" These layers have a lo$er refractive inde7than the centre layers! andhence confine the light effectively" Sch a design is called a separate confine#ent heterostrctre

5SC>6 laser diode"

Al#ost all co##ercial laser diodes since the :s have been SC> ,ant# $ell diodes"

Distributed feedback lasers

ain articleG Distribted feedbac& laser

Distribted feedbac& lasers5DF+6 are the #ost co##on trans#itter type inD-D)syste#s" Tostabili%e the lasing $avelength! a diffraction grating is etched close to the p)n 'nction of the

diode" This grating acts li&e an optical filter! casing a single $avelength to be fed bac& to the

gain region and lase" Since the grating provides the feedbac& that is re,ired for lasing! reflection

fro# the facets is not re,ired" Ths! at least one facet of a DF+ is anti)reflection coated" TheDF+ laser has a stable $avelength that is set dring #anfactring by the pitch of the grating!

and can only be tned slightly $ith te#peratre" DF+ lasers are $idely sed in optical

co##nication applications $here a precise and stable $avelength is critical"

The threshold crrent of this DF+ laser! based on its static characteristic! is arond :: #A" The

appropriate bias crrent in a linear regi#e cold be ta&en in the #iddle of the static characteristic

52 #A6"

VCSELs

ain articleG ?ertical)cavity srface)e#itting laser

Diagra# of a si#ple ?CSEL strctre* not to scale

?ertical)cavity srface)e#itting lasers5?CSELs6 have the optical cavity a7is along the direction

of crrent flo$ rather than perpendiclar to the crrent flo$ as in conventional laser diodes" The

active region length is very short co#pared $ith the lateral di#ensions so that the radiatione#erges fro# the srface of the cavity rather than fro# its edge as sho$n in the figre" The
http://en.wikipedia.org/wiki/Refractive_indexhttp://en.wikipedia.org/wiki/Distributed_feedback_laserhttp://en.wikipedia.org/wiki/Distributed_feedback_laserhttp://en.wikipedia.org/wiki/DWDMhttp://en.wikipedia.org/wiki/DWDMhttp://en.wikipedia.org/wiki/Anti-reflection_coatinghttp://en.wikipedia.org/wiki/Vertical-cavity_surface-emitting_laserhttp://en.wikipedia.org/wiki/Vertical-cavity_surface-emitting_laserhttp://en.wikipedia.org/wiki/File:Simple_vcsel.svghttp://en.wikipedia.org/wiki/File:Simple_vcsel.svghttp://en.wikipedia.org/wiki/Refractive_indexhttp://en.wikipedia.org/wiki/Distributed_feedback_laserhttp://en.wikipedia.org/wiki/Distributed_feedback_laserhttp://en.wikipedia.org/wiki/DWDMhttp://en.wikipedia.org/wiki/Anti-reflection_coatinghttp://en.wikipedia.org/wiki/Vertical-cavity_surface-emitting_laserhttp://en.wikipedia.org/wiki/Vertical-cavity_surface-emitting_laser


7/9

reflectors at the ends of the cavity are dielectric #irrors#ade fro# alternating high and lo$

refractive inde7 ,arter)$ave thic& #ltilayer"

Sch dielectric #irrors provide a high degree of $avelength)selective reflectance at the re,iredfree srface $avelength J if the thic&nesses of alternating layers d:and d@$ith refractive indices

n:and n@are sch that n:d:K n@d@ JM@ $hich then leads to the constrctive interference of allpartially reflected $aves at the interfaces" +t there is a disadvantageG becase of the high #irror

reflectivities! ?CSELs have lo$er otpt po$ers $hen co#pared to edge)e#itting lasers"

There are several advantages to prodcing ?CSELs $hen co#pared $ith the prodction process

of edge)e#itting lasers" Edge)e#itters cannot be tested ntil the end of the prodction process" If

the edge)e#itter does not $or&! $hether de to bad contacts or poor #aterial gro$th ,ality! theprodction ti#e and the processing #aterials have been $asted"

Additionally! becase ?CSELs e#it the bea# perpendiclar to the active region of the laser as

opposed to parallel as $ith an edge e#itter! tens of thosands of ?CSELs can be processed

si#ltaneosly on a three inch Balli# Arsenide $afer" Frther#ore! even thogh the ?CSELprodction process is #ore labor) and #aterial)intensive! the yield can be controlled to a #ore

predictable otco#e" >o$ever! they nor#ally sho$ a lo$er po$er otpt level"

Diunakan untuk

Laser diodes are n#erically the #ost co##on laser type! $ith @/ sales of appro7i#ately 0..

#illion nits!90;as co#pared to :.:! of other types of lasers"93;

Laser diodes find $ide se in teleco##nicationas easily #odlated and easily copled light

sorces for fiber opticsco##nication" They are sed in varios #easring instr#ents! sch as

rangefinders" Another co##on se is inbarcode readers"?isiblelasers! typically redbt lateralso green! are co##on as laser pointers" +oth lo$ and high)po$er diodes are sed e7tensivelyin the printing indstry both as light sorces for scanning 5inpt6 of i#ages and for very high)

speed and high)resoltion printing plate 5otpt6 #anfactring" Infraredand red laser diodes are

co##on in CD players! CD)ROsand D?Dtechnology" ?ioletlasers are sed in >D D?Dand+l)raytechnology" Diode lasers have also fond #any applications inlaser absorption

spectro#etry5LAS6 for high)speed! lo$)cost assess#ent or #onitoring of the concentration of

varios species in gas phase" >igh)po$er laser diodes are sed in indstrial applications sch asheat treating! cladding! sea# $elding and for p#ping other lasers! sch as diode)p#ped solid)

state lasers"

8ses of laser diodes can be categori%ed in varios $ays" ost applications cold be served bylarger solid)state lasers or optical para#etric oscillators! bt the lo$ cost of #ass)prodced diodelasers #a&es the# essential for #ass)#ar&et applications" Diode lasers can be sed in a great

#any fields* since light has #any different properties 5po$er! $avelength! spectral and bea#

,ality! polari%ation! etc"6 it is sefl to classify applications by these basic properties"

any applications of diode lasers pri#arily #a&e se of the =directed energy= property of anoptical bea#" In this category! one #ight inclde thelaser printers! barcode readers!i#age
http://en.wikipedia.org/wiki/Dielectric_mirrorhttp://en.wikipedia.org/wiki/Dielectric_mirrorhttp://en.wikipedia.org/wiki/Laser_diode#cite_note-7http://en.wikipedia.org/wiki/Laser_diode#cite_note-8http://en.wikipedia.org/wiki/Telecommunicationhttp://en.wikipedia.org/wiki/Optical_fiberhttp://en.wikipedia.org/wiki/Optical_fiberhttp://en.wikipedia.org/wiki/Rangefinderhttp://en.wikipedia.org/wiki/Barcode_readerhttp://en.wikipedia.org/wiki/Barcode_readerhttp://en.wikipedia.org/wiki/Visible_spectrumhttp://en.wikipedia.org/wiki/Redhttp://en.wikipedia.org/wiki/Greenhttp://en.wikipedia.org/wiki/Laser_pointerhttp://en.wikipedia.org/wiki/Infraredhttp://en.wikipedia.org/wiki/Compact_disc_playerhttp://en.wikipedia.org/wiki/CD-ROMhttp://en.wikipedia.org/wiki/CD-ROMhttp://en.wikipedia.org/wiki/DVDhttp://en.wikipedia.org/wiki/Violet_(color)http://en.wikipedia.org/wiki/HD_DVDhttp://en.wikipedia.org/wiki/Blu-ray_Dischttp://en.wikipedia.org/wiki/Laser_absorption_spectrometryhttp://en.wikipedia.org/wiki/Laser_absorption_spectrometryhttp://en.wikipedia.org/wiki/Laser_absorption_spectrometryhttp://en.wikipedia.org/wiki/Diode-pumped_solid-state_laserhttp://en.wikipedia.org/wiki/Diode-pumped_solid-state_laserhttp://en.wikipedia.org/wiki/Diode-pumped_solid-state_laserhttp://en.wikipedia.org/wiki/Laser_printerhttp://en.wikipedia.org/wiki/Laser_printerhttp://en.wikipedia.org/wiki/Image_scanninghttp://en.wikipedia.org/wiki/Image_scanninghttp://en.wikipedia.org/wiki/Dielectric_mirrorhttp://en.wikipedia.org/wiki/Laser_diode#cite_note-7http://en.wikipedia.org/wiki/Laser_diode#cite_note-8http://en.wikipedia.org/wiki/Telecommunicationhttp://en.wikipedia.org/wiki/Optical_fiberhttp://en.wikipedia.org/wiki/Rangefinderhttp://en.wikipedia.org/wiki/Barcode_readerhttp://en.wikipedia.org/wiki/Visible_spectrumhttp://en.wikipedia.org/wiki/Redhttp://en.wikipedia.org/wiki/Greenhttp://en.wikipedia.org/wiki/Laser_pointerhttp://en.wikipedia.org/wiki/Infraredhttp://en.wikipedia.org/wiki/Compact_disc_playerhttp://en.wikipedia.org/wiki/CD-ROMhttp://en.wikipedia.org/wiki/DVDhttp://en.wikipedia.org/wiki/Violet_(color)http://en.wikipedia.org/wiki/HD_DVDhttp://en.wikipedia.org/wiki/Blu-ray_Dischttp://en.wikipedia.org/wiki/Laser_absorption_spectrometryhttp://en.wikipedia.org/wiki/Laser_absorption_spectrometryhttp://en.wikipedia.org/wiki/Diode-pumped_solid-state_laserhttp://en.wikipedia.org/wiki/Diode-pumped_solid-state_laserhttp://en.wikipedia.org/wiki/Laser_printerhttp://en.wikipedia.org/wiki/Image_scanning


8/9

scanning! ill#inators! designators! optical data recording! co#bstion ignition! laser srgery!

indstrial sorting! indstrial #achining! and directed energy $eaponry" So#e of these

applications are $ell)established $hile others are e#erging"

Laser #edicineG #edicine and especially dentistry have fond #any ne$ ses for diode lasers"9;

9:;9::;

The shrin&ing si%e of the nits and their increasing ser friendliness #a&es the# veryattractive to clinicians for #inor soft tisse procedres" The 3 n# < 3 n# nits have a high

absorption rate for he#oglobin and ths #a&e the# ideal for soft tisse applications! $here goodhe#ostasisis necessary"

8ses $hich #ay #a&e se of the coherenceof diode)laser)generated light inclde interfero#etric

distance #easre#ent! holography! coherent co##nications! and coherent control of che#icalreactions"

8ses $hich #ay #a&e se of =narro$ spectral= properties of diode lasers inclde range)finding!

teleco##nications! infra)red conter#easres! spectroscopic sensing! generation of radio)

fre,ency or terahert% $aves! ato#ic cloc& state preparation! ,ant# &ey cryptography!fre,ency dobling and conversion! $ater prification 5in the 8?6! and photodyna#ic therapy

5$here a particlar $avelength of light $old case a sbstance sch asporphyrinto beco#e

che#ically active as an anti)cancer agent only $here the tisse is ill#inated by light6"

8ses $here the desired ,ality of laser diodes is their ability to generate ltra)short plses oflight by the techni,e &no$n as =#ode)loc&ing= inclde cloc& distribtion for high)perfor#ance

integrated circits! high)pea&)po$er sorces for laser)indced brea&do$n spectroscopy sensing!

arbitrary $avefor# generation for radio)fre,ency $aves! photonic sa#pling for analog)to)digital conversion! and optical code)division)#ltiple)access syste#s for secre co##nication"

SeeLaser diode lampLaser diodes are going to be sed forhigh bea# headlightsinAdivehicles" The high bea#s

$ill be lasers! thogh the lo$ bea#s $ill be light)e#itting diodes"The car #a&er says that theirhigh bea#s have a 2)#eter range! $hich is roghly t$ice the distance of LED high bea#s"

Lasers are e7pensive thogh" Lasers are s#aller! brighter and #ore energy efficient than LED

headla#ps" Their laser headla#ps se less than half the energy of LEDs" Laser diode can e#it

:0 l#ens per $att! $hile LEDs generate only : l#ens" Lasers are sensitive to heat bt thathasnt stopped their prodction for vehicles" Laser technology is not as advanced co#pared $ith

LEDs! $hich have been arond for decades"9:@;+ecase laser diodes have a range abot t$ice

that of an LED and are #ore then t$ice as efficient as LEDs! laser diodes are li&ely to beco#ethe standard in the ftre for high bea# head lights! flashlights and all other light sorces that

re,ire directional lighting"
http://en.wikipedia.org/wiki/Image_scanninghttp://en.wikipedia.org/wiki/Laser_surgeryhttp://en.wikipedia.org/wiki/Laser_medicinehttp://en.wikipedia.org/wiki/Laser_diode#cite_note-9http://en.wikipedia.org/wiki/Laser_diode#cite_note-10http://en.wikipedia.org/wiki/Laser_diode#cite_note-11http://en.wikipedia.org/wiki/Laser_diode#cite_note-11http://en.wikipedia.org/wiki/Hemostasishttp://en.wikipedia.org/wiki/Coherence_(physics)http://en.wikipedia.org/wiki/Tunable_Diode_Laser_Absorption_Spectrometryhttp://en.wikipedia.org/wiki/Porphyrinhttp://en.wikipedia.org/w/index.php?title=Laser_diode_lamp&action=edit&redlink=1http://en.wikipedia.org/wiki/Headlamp#High_beamhttp://en.wikipedia.org/wiki/Headlamp#High_beamhttp://en.wikipedia.org/wiki/Headlamp#High_beamhttp://en.wikipedia.org/wiki/Audihttp://en.wikipedia.org/wiki/Audihttp://en.wikipedia.org/wiki/Light-emitting_diodehttp://en.wikipedia.org/wiki/Light-emitting_diodehttp://en.wikipedia.org/wiki/Luminous_efficacyhttp://en.wikipedia.org/wiki/Laser_diode#cite_note-12http://en.wikipedia.org/wiki/Image_scanninghttp://en.wikipedia.org/wiki/Laser_surgeryhttp://en.wikipedia.org/wiki/Laser_medicinehttp://en.wikipedia.org/wiki/Laser_diode#cite_note-9http://en.wikipedia.org/wiki/Laser_diode#cite_note-10http://en.wikipedia.org/wiki/Laser_diode#cite_note-11http://en.wikipedia.org/wiki/Hemostasishttp://en.wikipedia.org/wiki/Coherence_(physics)http://en.wikipedia.org/wiki/Tunable_Diode_Laser_Absorption_Spectrometryhttp://en.wikipedia.org/wiki/Porphyrinhttp://en.wikipedia.org/w/index.php?title=Laser_diode_lamp&action=edit&redlink=1http://en.wikipedia.org/wiki/Headlamp#High_beamhttp://en.wikipedia.org/wiki/Audihttp://en.wikipedia.org/wiki/Light-emitting_diodehttp://en.wikipedia.org/wiki/Luminous_efficacyhttp://en.wikipedia.org/wiki/Laser_diode#cite_note-12


9/9

Documents

Diode Laser for Acne