# US 4,377,864 A · Chromium (III) ordered perovskite lasers and media therefor

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- Number: US 4,377,864 A
- Document ID: US4377864A
- Status: Granted
- Kind: A
- Application number: 06/291,664
- Filed: 1981-08-10
- Granted: 1983-03-22
- Earliest claimed: 1981-08-10
- Assignees: GTE Laboratories Incorporated
- Inventors: Bill C. McCollum; Leonard J. Andrews; Alexander Lempicki
- Web page: https://patentgrep.com/patent/US4377864A

## CPC

- H01S 3/1688: {Stoichiometric laser compounds, i.e. in which the active element forms one component of a stoichiometric formula rather than being merely a dopant}
- H01S 3/1623: {chromium, e.g. Alexandrite}
- H01S: DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL

## Abstract

A laser medium includes an ordered perovskite crystal of the general formula: A.sub.2 B Cr.sub.y B'.sub.1-y X.sub.6. A and B are alkali metal ions with the ionic radius of A greater than B. B' is an ion selected from the group consisting of Y.sup.3+, La.sup.3+, Gd.sup.3+, Lu.sup.3+, Sc.sup.3+, Al.sup.3+, Ga.sup.3+, and In.sup.3+. X is an ion selected from the group consisting of F.sup.-, Cl.sup.-, and Br.sup.-. A can be an ion selected from the group consisting of K.sup.+, Na.sup.+,Cs.sup.+, and Rb.sup.+. B can be an ion selected from the group consisting of K.sup.+-, Na.sup.+, and Li.sup.+. The chromium can be represented by Cr.sup.+3 ions. The laser media can be ordered perovskite polycrystalline compounds of the formulae: CsNaCr.sub.0.01 Y.sub.0.99 Cl.sub.6 ; KLi Cr.sub.y Sc.sub.1-y F.sub.6 (where y equals 0.01 and 0.10); K.sub.2 NaCr.sub.y Sc.sub.1-y F.sub.6 (where 0.01 .ltoreq.y.ltoreq.0.40). A laser can include an optical resonant cavity defined by a first totally reflective mirror and a second partially transmissive mirror. Within the cavity is an active laser medium comprising an ordered perovskite crystal of the general formula stated above, and may be of a specific formula as stated above. An optical pumping means is disposed adjacent to the optical cavity for exciting the laser medium to stimulated radiation. The mirrors are provided with reflective coatings on opposite surfaces of the active laser medium.

## Claims

### Claim 1

A laser medium comprising an ordered perovskite crystal of the general formula:
A.sub.2 BCr.sub.y B'.sub.1-y X.sub.6
where A and B are alkali metal ions with an ionic radius of A greater than B; B' is an ion selected from the group consisting of Y.sup.3+, La.sup.3+, Gd.sup.3+, Lu.sup.3+, Sc.sup.3+, Al.sup.3+, Ga.sup.3+, and In.sup.3+ ; and X is an ion selected from the group consisting of F.sup.-, Cl.sup.- and Br.sup.-.

### Claim 2 (depends on 1)

The lasers medium as recited in claim 1 wherein A is an ion selected from the group consisting of K.sup.+, Na.sup.+, Cs.sup.+, and Rb.sup.+ ; and B is an ion selected from the group consisting of K.sup.+, Na.sup.+, and Li.sup.+.

### Claim 3 (depends on 1)

The laser medium as recited in claim 1 wherein the chromium is represented by Cr.sup.+3 ions.

### Claim 4 (depends on 1)

The laser medium as recited in claim 1 wherein A is potassium.

### Claim 5 (depends on 1)

The laser medium as recited in claim 1 wherein B is lithium.

### Claim 6 (depends on 1)

The laser medium as recited in claim 1 wherein B is sodium.

### Claim 7

A laser medium comprising an ordered perovskite polycrystalline compound of the formula:
Cs.sub.2 NaCr.sub.0.01 Y.sub.0.99 Cl.sub.6.

### Claim 8

A laser medium comprising an ordered perovskite polycrystalline compound of the formula:
K.sub.2 LiCr.sub.y Sc.sub.1-y F.sub.6, where y=0.01 and 0.10.

### Claim 9

A laser medium comprising an ordered perovskite polycrystalline compound of the formula:
K.sub.2 NaCr.sub.y Sc.sub.1-y F.sub.6, where 0.01.ltoreq.y.ltoreq.0.40.

### Claim 10

A laser comprising in combination:
an optical resonance cavity defined by a first totally reflective mirror and a second partially transmissive mirror,
an active laser medium within said cavity, said medium comprising an ordered perovskite crystal of the general formula:
A.sub.2 BCr.sub.y B'.sub.1-y X.sub.6
where A and B are alkali metal ions with the ionic radius of A greater than B; B' is an ion selected from the group consisting of Y.sup.3+, La.sup.3+, Gd.sup.3+, Lu.sup.3+, Sc.sup.3+, Al.sup.3+, Ga.sup.3+, and In.sup.3+ ; and X is an ion selected from the group consisting of F.sup.-, Cl.sup.-, and Br.sup.-, and
an optical pumping means disposed adjacent to said optical cavity for exciting said laser medium to emit stimulated radiation,
wherein chromium is represented by Cr.sup.3+ ions,
wherein A is an ion selected from the group consisting of potassium, sodium, cesium, and rubidium; and B is selected from the group consisting of potassium, sodium, and lithium.

### Claim 11 (depends on 10)

The laser as recited in claim 10 where said active laser medium is an ordered perovskite polycrystalline compound of the formula Cs.sub.2 NaCr.sub.0.01 Y.sub.0.99 Cl.sub.6.

### Claim 12 (depends on 10)

The laser as recited in claim 10 wherein said active laser medium is an ordered perovskite polycrystalline compound of the formula K.sub.2 LiCr.sub.y Sc.sub.1-y F.sub.6, where y=0.01 and 0.10.

### Claim 13 (depends on 10)

The laser as recited in claim 10 wherein said active laser medium is an ordered perovskite polycrystalline compound of the formula K.sub.2 NaCr.sub.y Cs.sub.1-y F.sub.6, where 0.01.ltoreq.y.ltoreq.0.40.

### Claim 14 (depends on 10)

The laser as recited in claim 10 wherein said optical pumping means comprises at least one light emitting diode.

### Claim 15 (depends on 10)

The laser as recited in claim 10 wherein said first totally reflective mirror and said second partially transmissive mirror comprises reflective coatings on opposite surfaces of said active laser medium.