Patent US4209690A successfully refreshed from Google Patents.
← Back to Patent Explorer
US4209690A Expired / Lapsed US ⏱️ 0.0 years remaining

Induced absorption elements

Assignee: AT&T Inc
•
Filing: 1978-05-25
•
Granted: 1980-06-24
•
Expires: 1998-05-25
📄 Original PDF 🌐 Google Patents 🔄 Sync Now

Abstract

Abstract A class of elements is dependent upon induced absorption for transmitted energy. Absorption is introduced by first pumping an active medium to produce a first excited state--generally an electronically excited state--whereafter the energy level of such excited state is reduced to a lower "metastable" excited state or by pumping directly to such metastable state. Increased absorption for radiation of a quantum energy corresponding with the difference between the metastable and some higher excited state occurs during the time interval that population of the metastable state is maintained. Elements may operate as extremely rapid shutters, switches, modulators, pulse sharpeners, etc.

Inventors

  • 👤 Peter M. Rentzepis

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-25 09:32
CPC Classifications
H; H01; H01S; H01S3/00; H01S3/30; G; G02; G02F; G02F1/00; G02F1/35; G02F1/3523

Claims Analysis

Total Claims: 35
Claim 1
Independent Claim 257 words
In a communication system an apparatus including an element comprising an active medium, said active medium being characterized by quantum mechanical energy levels, together with first excitation means for exciting said active medium so as to increase population at at least one elevated quantum mechanical energy level to a population above that evidenced by the said medium when the medium is at thermodynamic equilibrium, the increased population at the said elevated level resulting in a "metastable state", said metastable state having an associated population lifetime defined as the time duration of such increased population at such metastable state with such defined time terminating upon spontaneous relaxation, characterized in that said apparatus includes a second means designated "associated radiation means" for making associated radiation incident upon said element, said associated radiation including energy of a quantum level to further excite the said medium from the metastable state to a first higher excited state whereby at least a portion of such associated radiation is absorbed with an associated extinction ratio greater than 99%, together with third means reponsive to a change in radiation amplitude of said associated radiation due to absorption resulting from excitation from said metastable state to the said first higher excited state, the apparatus further characterized in that the population of said metastable state varies in time over a time period of approximately 10 picoseconds in a manner representative of intelligence, whereby the said associated radiation is altered in a manner representative of the said intelligence, said intelligence being thereby replicated at the said third means.
Claim 2
Dependent Claim 257 words
In a communication system an apparatus including an element comprising an active medium, said active medium being characterized by quantum mechanical energy levels, together with first excitation means for exciting said active medium so as to increase population at at least one elevated quantum mechanical energy level to a population above that evidenced by the said medium when the medium is at thermodynamic equilibrium, the increased population at the said elevated level resulting in a "metastable state", said metastable state having an associated population lifetime defined as the time duration of such increased population at such metastable state with such defined time terminating upon spontaneous relaxation, characterized in that said apparatus includes a second means designated "associated radiation means" for making associated radiation incident upon said element, said associated radiation including energy of a quantum level to further excite the said medium from the metastable state to a first higher excited state whereby at least a portion of such associated radiation is absorbed with an associated extinction ratio greater than 99%, together with third means reponsive to a change in radiation amplitude of said associated radiation due to absorption resulting from excitation from said metastable state to the said first higher excited state, the apparatus further characterized in that the population of said metastable state varies in time over a time period of approximately 10 picoseconds in a manner representative of intelligence, whereby the said associated radiation is altered in a manner representative of the said intelligence, said intelligence being thereby replicated at the said third means.
Claim 3
Dependent Claim 14 words
Apparatus of claim 1 in which said first excitation means comprises a radiation means.
Claim 4
Dependent Claim 25 words
Apparatus of claim 2 in which said radiation means emits radiation including energy of a quantum level to produce direct excitation to said metastable state.
Claim 5
Dependent Claim 22 words
Apparatus of claim 3 in which the said metastable state and the said first higher excited state are within a single multiplet.
Claim 6
Dependent Claim 15 words
Apparatus of claim 4 in which the single multiplet is the ground state singlet multiplet.
Claim 7
Dependent Claim 34 words
Apparatus of claim 5 in which the energy difference between the said metastable state and first higher excited state corresponds with radiation of a wavelength beyond that of radiation contained within the visible spectrum.
Claim 8
Dependent Claim 14 words
Apparatus of claim 6 in which the said wavelength is in the infrared spectrum.
Claim 9
Dependent Claim 45 words
Apparatus of claim 1 in which said first excitation means includes a first portion for increasing energy from the said metastable state to a second higher excited state, which second higher excited state is at an energy level above that of the said metastable state.
Claim 10
Dependent Claim 31 words
Apparatus of claim 8 in which the said medium is characterized by energy levels which permit reduction of energy from said second higher excited state to said metastable state by relaxation.
Claim 11
Dependent Claim 13 words
Apparatus of claim 9 in which relaxation includes at least one radiationless transition.
Claim 12
Dependent Claim 38 words
Apparatus of claim 10 in which the said medium is characterized by a permitted transition from said second higher excited state to a metastable state of a multiplicity differing from that containing the said second higher excited state.
Claim 13
Dependent Claim 21 words
Apparatus of claim 11 in which said metastable state and said first higher excited state are both quantum mechanical triplet states.
Claim 14
Dependent Claim 22 words
Apparatus of claim 12 in which excitation from said metastable state to said first higher excited state is a single photon event.
Claim 15
Dependent Claim 21 words
Apparatus of claim 12 in which excitation from said metastable state to said first higher excited state is a multiphoton event.
Claim 16
Dependent Claim 33 words
Apparatus of claim 12 in which the said associated radiation means emits radiation characterized by a rise and fall in amplitude of a time interval less than that of the said population lifetime.
Claim 17
Dependent Claim 30 words
Apparatus of claim 15 in which the said associated radiation means produces pulsed radiation of such pulse rate that more than one pulse is produced within the said population lifetime.
Claim 18
Dependent Claim 16 words
Apparatus of claim 12 in which the said associated radiation means is a cw radiation source.
Claim 19
Dependent Claim 31 words
Apparatus of claim 8 in which said excitation means produces radiation including a second portion for stimulating a reduction in energy from said second higher excited state to said metastable state.
Claim 20
Dependent Claim 12 words
Apparatus of claim 18 in which said second portion produces stimulated emission.
Claim 21
Dependent Claim 33 words
Apparatus of claim 19 in which said second portion is pulsed and in which means is provided for time selection so as to produce stimulated emission of wavelength dependent upon such time selection.
Claim 22
Dependent Claim 14 words
Apparatus of claim 1 in which said second means is a cw radiation source.
Claim 23
Dependent Claim 13 words
Apparatus of claim 21 in which the third means includes a binary detector.
Claim 24
Dependent Claim 14 words
Apparatus of claim 21 in which the said third means includes an analog detector.
Claim 25
Dependent Claim 14 words
Apparatus of claim 21 in which the said second means comprises a cw laser.
Claim 26
Dependent Claim 13 words
Apparatus of claim 1 in which said second means is a pulse source.
Claim 27
Dependent Claim 13 words
Apparatus of claim 25 in which said pulse source is a pulsed laser.
Claim 28
Dependent Claim 13 words
Apparatus of claim 26 in which said pulsed laser is a mode-locked laser.
Claim 29
Dependent Claim 38 words
Apparatus of claim 1 in which the said first excitation means populates said metastable state in a time varying manner representative of information, whereby such information is replicated at the said third means as a corresponding amplitude variation.
Claim 30
Dependent Claim 14 words
Apparatus of claim 28 in which the said third means comprises a digital detector.
Claim 31
Dependent Claim 14 words
Apparatus of claim 28 in which the said third means comprises an analog detector.
Claim 32
Dependent Claim 31 words
Apparatus of claim 1 in which said excitation means includes a medium for increasing wavelength content via Stokes and anti-Stokes transformations and in which said third means includes wavelength selecting element.
Claim 33
Dependent Claim 13 words
Apparatus of claim 1 in which said third means comprises a transmission medium.
Claim 34
Dependent Claim 272 words
In a communication system, an apparatus including an element comprising an active medium, said active medium being characterized by quantum mechanical energy levels, together with first excitation means for exciting said active medium so as to increase population a at least one elevated quantum mechanical energy level to a population above that evidenced by the said medium when the medium is at thermodynamic equilibrium, the increased population at the said elevated level resulting in "metastable state", said metastable state having an associated population lifetime defined as the time duration of such increased population at such metastable state with such defined time terminating upon spontaneous relaxation, characterized in that said apparatus includes a second means designated "associated radiation means" for making associated radiation incident upon said element, said associated radiation including energy of a quantum level to further excite the said medium from the metastable state to a first higher excited state whereby at least a portion of such associated radiation is absorbed, together with third means responsive to a change in radiation amplitude of said associated radiation due to absorption resulting from excitation from said metastable state to the said first higher excited state, the apparatus further characterized in that the population of said metastable state varies in time in a manner representative of intelligence, whereby the said associated radiation is altered in a manner representative of the said intelligence, said intelligence being thereby replicated at the said third means, the apparatus further characterized in that said excitation means includes a medium for increasing wavelength content via Stokes and anti-Stokes transformations and in which said third means includes a wavelength selecting element.
Claim 35
Dependent Claim 272 words
In a communication system, an apparatus including an element comprising an active medium, said active medium being characterized by quantum mechanical energy levels, together with first excitation means for exciting said active medium so as to increase population a at least one elevated quantum mechanical energy level to a population above that evidenced by the said medium when the medium is at thermodynamic equilibrium, the increased population at the said elevated level resulting in "metastable state", said metastable state having an associated population lifetime defined as the time duration of such increased population at such metastable state with such defined time terminating upon spontaneous relaxation, characterized in that said apparatus includes a second means designated "associated radiation means" for making associated radiation incident upon said element, said associated radiation including energy of a quantum level to further excite the said medium from the metastable state to a first higher excited state whereby at least a portion of such associated radiation is absorbed, together with third means responsive to a change in radiation amplitude of said associated radiation due to absorption resulting from excitation from said metastable state to the said first higher excited state, the apparatus further characterized in that the population of said metastable state varies in time in a manner representative of intelligence, whereby the said associated radiation is altered in a manner representative of the said intelligence, said intelligence being thereby replicated at the said third means, the apparatus further characterized in that said excitation means includes a medium for increasing wavelength content via Stokes and anti-Stokes transformations and in which said third means includes a wavelength selecting element.

References Cited (Backward Citations)

DE1514411A1 Cited
US3842372A Cited
US3766498A Cited
US3864020A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1983-06-24 1983-12-24 1984-06-24 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1987-06-24 1987-12-24 1988-06-24 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1991-06-24 1991-12-24 1992-06-24 $7700.00 Window Closed / Lapsed

Assigned Categories & Tags

No categories assigned to this patent yet.

Assign Category Tag