Optically pumped liquid lasers

Claim 3

The device of claim 1 wherein said allowed electric dipole transition is a singlet-singlet transition.

Claim 4

The device of claim 1 wherein said means for exciting said organic material is light.

Claim 5

A laser comprising an active medium, said active medium comprising organic molecules capable of lasing in an allowed fluorescent transition when stimulated by radiation, and a source of stimulating radiation having a risetime not exceeding a few times the decay time between the first excited singlet state of said active medium and a triplet state of said active medium.

Claim 6

A laser comprising an active medium, said active medium comprising organic molecules capable of lasing in an allowed fluorescent transition when stimulated by radiation, and a source of stimulating radiation having a risetime not exceeding a few times the decay time between the first excited singlet state of said active medium and a triplet state of said active medium.

Claim 7

The invention as defined in claim 4 wherein the stimulated emission of the active medium takes place in a transition from the first excited singlet state to a vibrational level of the ground singlet state.

Claim 8

A laser comprising an active medium is an optical cavity, said active medium consisting of a metal porphyrin dissolved in a suitable solvent, and means for applying an excitation pulse to said active medium, said excitation pulse having a risetime less than a few times the mean decay time between the first excited singlet state and a triplet state of said active medium.

Claim 9

A laser comprising an active medium is an optical cavity, said active medium consisting of a metal porphyrin dissolved in a suitable solvent, and means for applying an excitation pulse to said active medium, said excitation pulse having a risetime less than a few times the mean decay time between the first excited singlet state and a triplet state of said active medium.

Claim 10

A laser as defined in claim 6 wherein said active medium is dissolved in an inorganic solvent.

Claim 11

A laser as set forth in claim 6 wherein said active medium is chloro-aluminum phthalocyanine dissolved in an organic solvent.

Claim 12

A laser as set forth in claim 8 wherein said solvent is ethyl alcohol. 10 A laser as defined in claim 6 wherein said solvent is concentrated H2SO4.

Claim 13

A laser comprising an active medium in an optical cavity, said active medium consisting of chloro-aluminum phthalocyanine dissolved in an organic solvent, means for applying a lasing pulse of a frequency of 6943A. and risetime not exceeding approximately a few times the decay time between the first excited singlet state and a triplet state of said active medium to said active medium, whereby said active medium lases at a frequency of about 7560A.

Claim 14

A laser comprising an active medium in an optical cavity, said active medium consisting of chloro-aluminum phthalocyanine dissolved in an organic solvent, means for applying a lasing pulse of a frequency of 6943A. and risetime not exceeding approximately a few times the decay time between the first excited singlet state and a triplet state of said active medium to said active medium, whereby said active medium lases at a frequency of about 7560A.

Claim 15

A laser as defined in claim 11 wherein said optical cavity comprises two parallel reflecting mirrors, one on either side of said active medium, one of said mirrors being partially transmissive to electromagnetic energy having a frequency of 7560A.

Claim 18

The device of claim 13 wherein a solvent of said dye is any one of the group consisting of ethyl, methyl, propyl, or butyl alcohol.

Claim 19

The device of claim 13 wherein a solvent for said dye is dimethyl sulfoxide or dimethyl formamide.

Claim 20

The Device of claim 13 wherein a solvent for said dye is ethylene glycol or glycerin.

Claim 21

A laser comprising an active medium in an optical cavity, said active medium consisting of a solution of the photosensitizing dye 3, 3'' - diethylthiatricarbocyanine iodide in a transparent cylinder having two ends, and means for applying a lasing pulse at one end of said transparent cylinder for applying pumping energy to said active medium, said lasing pulse having a risetime less than a few times the mean decay time between the first excited singlet state and a triplet state of said active medium.

Claim 22

A laser comprising an active medium in an optical cavity, said active medium consisting of a solution of the photosensitizing dye 3, 3'' - diethylthiatricarbocyanine iodide in a transparent cylinder having two ends, and means for applying a lasing pulse at one end of said transparent cylinder for applying pumping energy to said active medium, said lasing pulse having a risetime less than a few times the mean decay time between the first excited singlet state and a triplet state of said active medium.

Claim 23

A laser comprising a solution of the photosensitizing dye 3, 3'' - diethylthiatricarbocyanine iodide disposed in a first optical cavity comprising first and second parallel mirrors, a second optical cavity for producing a high energy output pulse having a risetime less than approximately a few times the decay time between the first excited singlet state and a triplet state of said active medium to pump said dye and lying coaxially of said first optical cavity, said first mirror being common to both optical cavities and being highly transmissive to said pumping energy but highly reflective of an output lasing pulse produced by said dye solution, and said second mirror being transmissive of the output lasing frequency of said dye solution.

Claim 24

A laser comprising a solution of the photosensitizing dye 3, 3'' - diethylthiatricarbocyanine iodide disposed in a first optical cavity comprising first and second parallel mirrors, a second optical cavity for producing a high energy output pulse having a risetime less than approximately a few times the decay time between the first excited singlet state and a triplet state of said active medium to pump said dye and lying coaxially of said first optical cavity, said first mirror being common to both optical cavities and being highly transmissive to said pumping energy but highly reflective of an output lasing pulse produced by said dye solution, and said second mirror being transmissive of the output lasing frequency of said dye solution.

Claim 25

A laser comprising an active medium comprising organic molecules having ground state energy levels and energy levels of a first excited singlet state and of a triplet state, said organic molecules being in a lasing condition when a sufficient threshold population inversion exists between said first excited singlet state and said ground state, there being decay transitions between said excited singlet state and said triplet state which deplete the population of said first excited singlet state reducing said population inversion; a source of stimulating light for establishing said lasing condition in said molecules, said light having a risetime which is less than the time required for said decay transitions to reduce said population inversion below said sufficient population inversion.

Claim 26

A laser comprising an active medium comprising organic molecules having ground state energy levels and energy levels of a first excited singlet state and of a triplet state, said organic molecules being in a lasing condition when a sufficient threshold population inversion exists between said first excited singlet state and said ground state, there being decay transitions between said excited singlet state and said triplet state which deplete the population of said first excited singlet state reducing said population inversion; a source of stimulating light for establishing said lasing condition in said molecules, said light having a risetime which is less than the time required for said decay transitions to reduce said population inversion below said sufficient population inversion.

Claim 29

The laser of claim 20, wherein said allowed electric dipole transition is a singlet-singlet fluorescent transition.

Claim 30

The laser of claim 20, further including a resonant cavity in which said fluorescent organic material is located.

Claim 31

A laser, comprising: a fluorescent organic material having an allowed electric dipole fluorescent transition, said organic material having ground state energy levels and energy levels of a first excited singlet state and of a triplet state, said organic material being in a lasing condition when a sufficient population inversion exists between said first excited singlet state and said ground state, there being non-radiative decay transitions between said excited singlet state and said triplet state which deplete the population of said first excited singlet state and provide optical loss in said active medium, thereby tending to prevent said lasing; a source of electromagnetic radiation for excitation of said fluorescent material to estAblish said lasing in said organic material, said electromagnetic radiation having a risetime which is less than the time required for said decay transitions to produce sufficient losses for prevention of said lasing between said excited singlet state and said ground state.

Claim 32

A laser, comprising: a fluorescent organic material having an allowed electric dipole fluorescent transition, said organic material having ground state energy levels and energy levels of a first excited singlet state and of a triplet state, said organic material being in a lasing condition when a sufficient population inversion exists between said first excited singlet state and said ground state, there being non-radiative decay transitions between said excited singlet state and said triplet state which deplete the population of said first excited singlet state and provide optical loss in said active medium, thereby tending to prevent said lasing; a source of electromagnetic radiation for excitation of said fluorescent material to estAblish said lasing in said organic material, said electromagnetic radiation having a risetime which is less than the time required for said decay transitions to produce sufficient losses for prevention of said lasing between said excited singlet state and said ground state.

Claim 33

A coherent radiation device, comprising: a fluorescent material having organic molecules capable of lasing in an allowed fluorescent transition when excited by energy which produces a critical population inversion in a singlet system of said fluorescent material said organic material having decay transitions which populate a triplet state of said organic molecules; excitation means for exciting said fluorescent material with energy having a risetime sufficiently fast to produce said critical inversion, said risetime being less than the time required for gain in said singlet system to be nullified by losses resulting from accumulation of said molecules in said triplet state of said fluorescent material.

Claim 34

A coherent radiation device, comprising: a fluorescent material having organic molecules capable of lasing in an allowed fluorescent transition when excited by energy which produces a critical population inversion in a singlet system of said fluorescent material said organic material having decay transitions which populate a triplet state of said organic molecules; excitation means for exciting said fluorescent material with energy having a risetime sufficiently fast to produce said critical inversion, said risetime being less than the time required for gain in said singlet system to be nullified by losses resulting from accumulation of said molecules in said triplet state of said fluorescent material.