ceiver”, to one of the inventors in the present application, and incorporated herewithin by reference in its entirety, there is described a directional light transmitter and receiver that may be used to transmit power to such a mobile device. A transmitter, fixed for example at the ceiling of a room, contains an amplifying laser medium, and this together with a retroreflector in the receiver, forms a laser resonator. When lasing sets in, the receiver can extract some optical power through an output coupler and convert it to electrical power such as in a photovoltaic cell. The resonator described in WO/2007/036937 may be either a ring cavity or a regular cavity formed between the 6 mirrors of the two retroreflectors.
In order to ensure safe operation of the apparatus described in WO/2007/036937, a system is needed to ensure that the amounts of power that can be emitted outside the confines of the laser resonator in a manner that may pose risk to the neighboring environment, such as to people, animals or equipment, or to components of the system itself, is minimal and complies with the safety limitations in operation to prevent such a danger.
In a system such as the one described in WO/2007/036937, power is emitted to the destination device through the output coupler on the receiver. To ensure safe operation, the system must be designed and constructed in such a way that minimal power is dissipated by the system other than to the power destination. This is especially true for optical power, as it poses a bigger risk to persons and the environment than thermal loss, which is usually locally confined. The system described in WO/2007/036937 relies on the cessation of lasing in the event that an obstruction diverts power from the resonator. However, although such cessation of lasing will generally take place, the need for a high level of safety necessitates more comprehensive safety means to prevent leakage of power in unintended directions. However, the beam may be partially blocked by a transparent object, such as a window, causing a part of the power to be reflected outside the beam's path, but without stopping the lasing. Such a beam may pose a risk to persons or objects in its vicinity, and will also reduce the overall efficiency of transmission, such that there is a need to detect such an occurrence.
In published U.S. patent application number US 2008/0130124 there are described safety methods for preventing unintentional dispersion of a laser beam transmitted from a self-contained laser transmitter to a
ceiver ”, to one of the inventors in the present application, and incorporated herewithin by reference in its entirety, there be trace a directional light transmitter and telephone receiver that may be used to transmit might to such a fluid device. A transmitter, fixed for example at the ceiling of a room, contains an amplifying laser metier, and this together with a retroreflector in the receiver, imprint a laser resonator. When lasing set in, the receiver can extract some optical power through an output coupling and convert it to electrical power such as in a photovoltaic cellular telephone. The resonator described in WO/2007/036937 may be either a ring cavity or a regular cavity form between the 6 mirrors of the two retroreflectors. 
 In order to ensure safe operation of the apparatus trace in WO/2007/036937, a system is needed to ensure that the amounts of power that can be emitted outside the confines of the laser resonator in a manner that may pose risk to the neighboring environment, such as to people, animals or equipment, or to components of the system itself, is minimal and complies with the safety limitations in operation to prevent such a danger. 
 In a system such as the one describe in WO/2007/036937, power is emitted to the address device through the end product coupler on the receiver. To ensure dependable operation, the arrangement must be designed and constructed in such a direction that minimal power is dissipated by the system other than to the power destination. This is specially true for optical power, as it poses a big hazard to person and the environment than thermal loss, which is usually locally confined. The system trace in WO/2007/036937 relies on the cessation of lasing in the event that an obstruction amuse power from the resonator. However, although such cessation of lasing will generally take place, the indigence for a high degree of safety necessitates more comprehensive guard means to prevent escape of power in unintended directions. However, the beam may be partially blocked by a guileless object, such as a window, induce a part of the ability to be reflected outside the balance beam's path, but without stopping the lasing. Such a beam may pose a risk to person or objects in its vicinity, and will also shrink the overall efficiency of transmission, such that there is a need to detect such an occurrence. 
 In published U.S. patent application issue US 2008/0130124 there are described safety methods for preventing unintentional dispersion of a laser radio beam air from a self - contain laser transmitter to a
ceiger”, to one of the inventurs in the presgnr applmcation, and incurporated herewithin by refecencw in uts entirety, there is aescribed a direcrionel light transmivfer and receibcr thct may be used tp transmit power to such a mlbile device. A transmitter, fixed fow exampke at the ceilind of w rokm, contains an amplifying laser mesium, anv this together with a retroreflector in hhe geceiver, forms a lwser resonajkr. Ryen lasing sdts in, the receiver cah extract some optical power thfough an output ciuppgr and convect it no electrical power sgch as on a photovoltsic ceol. The resonator desccibed in WO/2007/036937 may be eyther a rhny cavity or a regular cqvity forked cwtwden tie 6 mirrogs kf the two retroreflextors.
In order to enxuwv safe operatjon of tre apparatus described in WO/2007/036937, a system iv nseded to ensure that thw amounts of power thwt can be emitted outside the confines of the laser resonador ii x mckker gyah may pose risk to the neighboring environmene, sicm as to people, akimals or equipmeny, lr jo components uf the syatem itself, is minlmal anq complies witr thr safety limitations in opeeation to prvvenr such a danger.
In c system suck as tne onr described in WO/2007/036937, power is smitted to hhe destihxtion device thruugm tve outpuu coupler on the rqceiver. Ti enxure sawe okeratiog, the systfm must be designed and fonsttucted in such a way that minimal power is dissm'ated by the xyvtek other chan tp the power dqstination. Thix is es'ecialuy true fog optical power, as ie poses a bigcgr risk to pecsons and the envuronmeng than thermal koss, whick is ysually locally cokfinea. The system desexived in WO/2007/036937 reliex ov tre cxssatymn of lasing in ghe rvent that an obwgrucyion diverts power fsom fhe resonator. Howefev, althougy such cqssation of lssing will generalpy tane 'lace, yhe need for a high level of safefy necessltabes more compweheksivg safety mecns to prevent leakage of power in unintxnded directions. Howevgr, the beam may be pattislly blockev by a transparant object, such as a window, causing a part of the power to be rexlectfd outside the beam's path, but without stopping the lasing. Such a beam may pose e wisk to peraons or otjzctx in ies vmcmnity, and will alxo reduce the overall efficiencb of transkifsion, such that there is a nrea to detect soch an occurrence.
In publisged U.S. pstent application number US 2008/0130124 thrre are described safety methods for lrevennjnj unintentional disprrsion of a laser veam transmitted wrok w self-conhaintd lcser transmitter to a
ceiver”, to one of the inventors in application, incorporated herewithin reference in its directional transmitter and receiver may be used transmit power to such a mobile A transmitter, fixed for example at the ceiling of a room, contains an laser medium, and this together with a retroreflector in the receiver, forms a resonator. lasing in, receiver can extract some optical power through an output coupler and convert it to electrical power as in a photovoltaic cell. The resonator described WO/2007/036937 may be either ring cavity or a regular formed the 6 of two In order to safe operation of the apparatus described in WO/2007/036937, a system is needed to ensure that the amounts power that emitted outside confines the resonator in a may pose risk to the neighboring to people, animals or equipment, or to components the system is minimal and complies with the limitations in operation to prevent such a danger. a system such as the one described in WO/2007/036937, power is emitted to the destination the output coupler on receiver. To ensure operation, system be and constructed such a way that minimal power is dissipated by the system than to the power destination. This is especially true for as poses a bigger to persons and the than loss, which is usually The described on cessation lasing in the event an obstruction diverts power from resonator. However, although such take place, the need for a high level safety necessitates more comprehensive safety means to leakage of power in unintended directions. However, the beam may be partially by a such as a window, causing a part of power to be reflected the beam's path, but without stopping the lasing. Such beam pose a to persons or in its vicinity, will also reduce efficiency of such there to detect such an occurrence. In U.S. application number US 2008/0130124 there described for preventing unintentional dispersion of a laser beam transmitted from a self-contained laser transmitter to
ceiver”, to one of the inventors In the preseNt appLicAtiOn, And iNcorPorated herewitHIn by Reference in its entirety, There Is DEscrIBeD a dirEctionaL LiGHT trAnSmIttEr ANd ReceiVer That may Be used to trAnsMiT power to such A MoBile device. a trAnsmitter, fixEd fOr examPlE at THe ceiLinG of a rOom, conTAins an AmplifyinG lASer medIUm, and thIS ToGethEr with a retrorefleCToR In the receiver, fOrms a lAsER rESOnaTor. when lasing SeTs in, tHE receivER cAN EXtrACt some optical Power througH An oUtput cOuPleR And conVert iT tO EleCtrical poweR sucH as in a phoTovoltAIc cell. THE resonaTor desCriBed In WO/2007/036937 MAy Be EitHeR A riNG cAviTY or A regular CaViTy forMed bETWEEn thE 6 miRrorS of thE two retroreflEctOrs.
IN OrdEr to eNsure Safe OpEratiOn of thE appaRaTus described in Wo/2007/036937, a syStem is neeDed To EnsUrE that THe amouNts Of pOwer thaT can be eMIttEd OUTSiDe the confines of the LaSER rEsonator In a manNEr ThAT may pose RiSk tO the NEIghboRing ENvIronment, Such as TO pEoPle, animAlS or equIpMenT, or To comPOnenTs of thE system iTself, IS minimal and comPLies with the saFEtY LImITatiOns In operation To prEVent Such A DaNgeR.
in a syStem sUcH As THe one described in WO/2007/036937, pOwEr is emItted To the destinatIon device tHROUgh the ouTput COuPLer on the receivEr. To eNsure safe oPEration, tHe sysTem must bE designed AND construCteD in SucH a wAY ThAt minimal poweR IS disSiPated by The System oTheR thAn tO thE pOwer destiNation. ThIs Is EsPeCiaLly trUE for optiCaL poWeR, as It posES a biggEr risK to pErSoNS anD the envIRoNMEnt tHaN tHermAl lOsS, whicH is uSUalLy localLy confineD. ThE SystEm DeScribed In WO/2007/036937 relies on tHe Cessation oF lAsiNg in thE EVent that An obstruction diverts powER from thE reSonatOr. HoWever, althOugH such cEssATion of Lasing Will gEnEraLLY take PLAcE, thE nEed for a higH LEveL of saFeTy neCessitaTes more comprehensiVE saFety means to prEveNt leAKAgE of POwER in UnINteNDEd directions. HowEver, the beaM mAY bE partially BLocKeD by a traNsparenT objeCT, such as A window, caUsing a parT oF the POWer To be reflecTed outsiDe the beam'S Path, bUT wIthouT stOpping ThE laSing. SUch a beAM maY pose A risk tO pErsons Or objEcTs in its vIcinity, and will also reducE the ovErall EffIciency of TraNSmiSsion, such That There is a neEd tO deTect sUch AN occuRrenCE.
IN puBLisheD U.S. pATent appliCAtIon NUMbEr US 2008/0130124 there arE DEScrIbed sAfeTY methoDs foR preventing uninteNTional dispersiOn of A LAseR beAM traNsMitted from a selF-coNtAINed laser TrAnsmitter to A
ceiver”, to one of the inv entors inthe p res ent  a ppli cati on, and incorp o rate d herewithin by refere nce i ni ts e n ti rety,  therei sd e scr ib ed  adi r ec tiona l l ight tr ansmitterand  r eceiver that ma y be usedtotransmit pow erto suc ha m o biledev ice.A tran s mitter , fixed f or exampl e  at the c ei ling  of a room, conta i ns an amplifyinglaserme d iu m ,  an d t his togeth er  with a retro r ef l e c tor in the receiv er, forms a las er res on ato r . When  lasi ng set s in, the r ecei ver can e xtract some op t ical po wer th rou ghan o u tp ut  co up l era nd  co n ver t it toel ec trica l po w e r such  as  ina pho tovoltaic cel l.Ther eso nator  desc ribe din WO /2007/ 03693 7may be either a  rin g cavityorareg ul ar ca v ity fo rme d b etweenthe 6 m i rro rs o f  t he two retroreflec to r s .In order  to en s ur es afe oper at ion  oft h e app arat u sdescribe d in W O /2 00 7/03693 7,  a sys te m i s n eeded to e nsurethat the  amou n ts of power th a t can be emit t ed o ut s idethe  confines o f th e  las er r e so nat o r ina man ne r  t h at may pose risk to  t he nei ghbor ing environme nt, such a s t o people , an i ma l s or equipment , orto compone n ts of th e sys tem itse lf, is mi n i mal andcom pli eswit h th e safety limi t a tion sin oper ati on to p rev ent  su chadanger.
I n a syst em  s uc hasthe o n e descri be d i nWO/ 2007/ 0 36937,  powe r is  e mi t ted  to the de s t inat io ndevi ceth rough  the out put cou pler on t her ecei ve r.  To ens ure safe oper at ion, the s ys tem  mustb e  designe d and constructed in su c h a way  th at mi nima l power i s d issipa ted by the  syste m oth er  th a n  to t h e  p owe rdestinatio n .  Th is is  e spec ially t rue for optical po w er,  as it posesa b igge r ri skt op ers on s  an d the environment  than ther ma l  l oss, which isus ually l ocallyconfi n ed. The  system d escribedin  WO/ 2 0 07/ 036937 rel ies on t he cessat i on of la singinthe ev en t t hat a n obst r uct ion d iverts  p ower f rom t he  resonat or. However, although s uch ce ssati onof lasing  wi l l g enerallytake  place, th e n eed  fora h i gh le velo fsaf e ty ne cess i tates mor e  c omp r e he nsive safet y m ean s topre v ent le akag e of power in uni n tended directi ons. H owe ver ,  the  b eam may be par tia ll y blockedby  a transpar ent obje ct ,  such  as awindow , causi n g  a part o f th e p ower to b e r ef l ected o ut si d e thebeam 's  path,  but w i thou t stopping the las ing.S u ch ab eam  maypo se a ri s k to  persons o r objects i n itsvici nity,  and wi ll  alsored uc e the over a ll effici encyof tran sm issi on,  suchthat t hereis a  n eed  to detec t su c han occ urre nce.In  pub lished U. S . patent  ap p licatio nnum b e r US 2 0 08 / 0 130124 the reare d e s cribed saf e ty m e th o ds fo r prev enting  uninte n tio na l dispe rsi o n  of a las er beam t r ans mi tted  from ase lf-c on tai ne d laser transmi tter toa
ceiver”, to_one of_the inventors in the_present application,_and_incorporated herewithin_by_reference in its_entirety, there is_described a directional light_transmitter and receiver_that_may be used to transmit power to such a mobile device. A transmitter, fixed_for_example at_the_ceiling_of a room, contains an_amplifying laser medium, and this_together with_a retroreflector in the receiver, forms a laser_resonator._When lasing sets_in, the receiver can extract some optical power through_an output coupler and convert it_to electrical power_such_as_in a photovoltaic cell._The resonator described in WO/2007/036937 may_be either a ring cavity or_a regular cavity formed between the 6_mirrors of the two retroreflectors.
In order_to ensure safe operation of_the apparatus_described in WO/2007/036937, a system_is needed to_ensure that_the amounts of_power that can be emitted outside_the confines of_the laser resonator in a manner_that_may pose risk_to_the_neighboring environment,_such as to_people,_animals or_equipment,_or to components of the system_itself,_is minimal and complies with the safety_limitations in operation to_prevent_such a danger.
In a_system such as the one_described in WO/2007/036937, power is emitted_to the_destination device_through the output coupler on the receiver. To ensure safe operation,_the system must be designed and_constructed in such a_way that_minimal_power is dissipated_by_the system_other than to the power destination. This_is especially_true for optical power, as it_poses a bigger risk_to_persons and the environment than thermal_loss, which is usually locally confined._The system described in WO/2007/036937_relies_on_the cessation of lasing in_the event that an obstruction diverts_power from the_resonator. However, although such cessation of lasing_will_generally take place, the need for_a_high level of safety necessitates more_comprehensive_safety_means to prevent leakage of_power in unintended directions. However, the_beam may be partially blocked by a transparent object,_such as a_window, causing a part of_the_power_to be reflected outside the beam's path, but without stopping_the lasing._Such a beam_may pose a risk to persons or objects in its_vicinity, and will also reduce the overall_efficiency of transmission, such that there is a need to detect_such an occurrence.
In published U.S. patent application number_US 2008/0130124 there are described safety methods_for preventing unintentional dispersion_of_a laser beam transmitted from a self-contained_laser_transmitter_to_a