jc@saber.UUCP (John Cincotta) (01/23/86)
I just heard a discussion of a Fabre Preot interformeter. It involved the
use of 2 mirrors that had 95 % reflectance and 5 % transmission they were
set up parrellel to each other and a given number of wavelengths apart.
It was stated that if this device was raidated with 1 watt of light at that
waveleignth the output at the other end would be 1 watt. And that there would
be 20 wats of energy raidateing back and forth between the mirrors.
Is this realy true and if so how does it work????
Name: John Cincotta
Mail: Saber Technology, 2381 Bering Drive, San Jose, California 95131
AT&T: 435-8600
UUCP: ...{decvax,ucbvax}!decwrl!saber!jc
...{amd,ihnp4,ittvax}!saber!jcsutin@astrovax.UUCP (Brian M. Sutin) (01/24/86)
> I just heard a discussion of a Fabre Preot interformeter. It involved the > use of 2 mirrors that had 95 % reflectance and 5 % transmission they were > set up parrellel to each other and a given number of wavelengths apart. > It was stated that if this device was raidated with 1 watt of light at that > waveleignth the output at the other end would be 1 watt. And that there would > be 20 wats of energy raidateing back and forth between the mirrors. > Is this realy true and if so how does it work???? > Just like a computer... you put 200 lines of garbage code in, it gives you 200 lines of garbage data out. And it always has 800 megabytes of disk storage being used for useless junk. Brian Sutin Department of Astrophysical Sciences Princeton University { allegra, akgua, cbosgd, decvax, ihnp4, noao, philabs, princeton, vax135 } !astrovax!sutin
piner@pur-phy.UUCP (Richard Piner) (01/25/86)
In article <1917@saber.UUCP> jc@saber.UUCP (John Cincotta) writes: >I just heard a discussion of a Fabre Preot interformeter. It involved the >use of 2 mirrors that had 95 % reflectance and 5 % transmission they were >set up parrellel to each other and a given number of wavelengths apart. >It was stated that if this device was raidated with 1 watt of light at that >waveleignth the output at the other end would be 1 watt. And that there would >be 20 wats of energy raidateing back and forth between the mirrors. >Is this realy true and if so how does it work???? > That's Fabry-Perot interferometer. For a full description see Jenkins and White. To explain in brief, an interfermometer acts as a RF resonance cavity. The energy between the mirrors is stored as a standing wave. The ratio of stored energy to radiated energy is the "Q". This all makes sense to anyone with an EE backround. I have a hell of a time explaining it to particle physicist however. If you want to know more, come to Purdue and take my couse in optics. Rich Piner Purdue Physics Dept. piner@pur-phy.UUCP
stern@bnl.UUCP (Eric G. Stern) (01/26/86)
> I just heard a discussion of a Fabre Preot interformeter. It involved the > use of 2 mirrors that had 95 % reflectance and 5 % transmission they were > set up parrellel to each other and a given number of wavelengths apart. > It was stated that if this device was raidated with 1 watt of light at that > waveleignth the output at the other end would be 1 watt. And that there would > be 20 wats of energy raidateing back and forth between the mirrors. > Is this realy true and if so how does it work???? > > Name: John Cincotta > Mail: Saber Technology, 2381 Bering Drive, San Jose, California 95131 > AT&T: 435-8600 > UUCP: ...{decvax,ucbvax}!decwrl!saber!jc > ...{amd,ihnp4,ittvax}!saber!jc The major problem with this statement is that the energy content of the Fabry-Perot cavity cannot be expressed in watts since watts = energy/time is a unit of power. The power into the FP system is equal to the power out of the system except for losses in the mirrors and walls. Since the system you describe has equal mirrors on both ends, the power coming out of the cavity must be the same on both the front and back sides. Assuming that no absorption takes place and that 1 watt of power enters the cavity, then 0.5 watt must leave the cavity on either side. Now look in particular at one of the mirrors. Since the mirror is 5% transmitting and 0.5 watts is transmitted through the mirror, then 10 watts must be incident on the mirror which is 20 times the transmitted power. There is no great mystery in this. You can't fool me young man, Eric G. Stern it's turtles all the way down! Dept. of Physics, SUNY stern@bnl.arpa stern@bnl.bitnet BNLCL{1-4}::STERN (HEPnet)
rpt@warwick.UUCP (Richard Tomlinson) (01/27/86)
Sender: Followup-To: Keywords: Xref: ukc net.physics:3191 net.astro.expert:60 Xpath: ukc eagle In article <1917@saber.UUCP> jc@saber.UUCP writes: >I just heard a discussion of a Fabre Preot interformeter. >It was stated that if this device was raidated with 1 watt of light at that >waveleignth the output at the other end would be 1 watt. And that there would >be 20 wats of energy raidateing back and forth between the mirrors. Since when has the watt been a measure of energy? I learnt the unit was joule at 'O' level. -- -------------------------------------------------------------------- ...!mcvax!ukc!warwick!rpt
lambert@boring.uucp (Lambert Meertens) (01/28/86)
>>I just heard a discussion of a Fabre Preot interformeter. It involved the >>use of 2 mirrors that had 95 % reflectance and 5 % transmission they were >>set up parrellel to each other and a given number of wavelengths apart. >>It was stated that if this device was raidated with 1 watt of light at that >>waveleignth the output at the other end would be 1 watt. And that there would >>be 20 wats of energy raidateing back and forth between the mirrors. >>Is this realy true and if so how does it work???? > That's Fabry-Perot interferometer. For a full description see >Jenkins and White. To explain in brief, an interfermometer acts as >a RF resonance cavity. The energy between the mirrors is stored as >a standing wave. The ratio of stored energy to radiated energy is >the "Q". This all makes sense to anyone with an EE backround. I have >a hell of a time explaining it to particle physicist however. If >you want to know more, come to Purdue and take my couse in optics. To unsterdand hwy teh Farby-Perto inferthermometer sttores 20 what you dont need a baground in EE. Pur unit of time you put in 1 freeble of enrgy and outcomes 5% off watt is stored, so if thats less than 20 freebles it incresaes and if more it dinimishes, so it setless on 20 only its not wats but freebles (the dimension of "Watt" is energy/time) and to obtain the energy you have to multiply 20 W by the time it takes the wave to move from one end to the other, which is not much. -- Lambert Meertens ...!{seismo,okstate,garfield,decvax,philabs}!lambert@mcvax.UUCP CWI (Centre for Mathematics and Computer Science), Amsterdam