# US 2017/0288079 A1 · Two-stage light concentrator

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- Number: US 2017/0288079 A1
- Document ID: US20170288079A1
- Status: Published application
- Kind: A1
- Application number: 15/083,742
- Filed: 2016-03-29
- Published: 2017-10-05
- Earliest claimed: 2016-03-29
- Assignees: X Development LLC
- Applicants: X Development LLC
- Inventors: Martin F. Schubert
- Web page: https://patentgrep.com/patent/US20170288079A1

## CPC

- H10F 77/45: Wavelength conversion means, e.g. by using luminescent material, fluorescent concentrators or up-conversion arrangements
- G02B 19/00: Condensers, {e.g. light collectors or similar non-imaging optics}(for microscopes G02B21/08)
- H01S 3/0915: by incoherent light
- H01S 3/169: {Nanoparticles, e.g. doped nanoparticles acting as a gain material}
- H10F 77/488: {Reflecting light-concentrating means, e.g. parabolic mirrors or concentrators using total internal reflection}
- H01S 3/0612: {Non-homogeneous structure (H01S3/07 takes precedence)}
- H01S 3/063: Waveguide lasers, {i.e. whereby the dimensions of the waveguide are of the order of the light wavelength (waveguide gas lasers H01S3/0315)}
- H01S 3/093: focusing or directing the excitation energy into the active medium
- H01S 3/09403: {Cross-pumping, e.g. Förster process involving intermediate medium for excitation transfer}
- Y02B 10/10: Photovoltaic [PV]
- Y02E 10/50: Photovoltaic [PV] energy
- Y02E 10/52: PV systems with concentrators
- H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- 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
- Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

A light concentrator includes a luminescent concentrator and a gain medium. The luminescent concentrator includes a semiconductor material and the semiconductor material absorbs first photons. The first photons have energy greater than or equal to a threshold energy, and the semiconductor material emits second photons through a spontaneous emission process where the second photons have less energy than the first photons. The gain medium is optically coupled to the luminescent concentrator to receive the second photons. The gain medium absorbs the second photons, and in response to absorbing the second photons, the gain medium emits third photons through a stimulated emission process. The third photons have less energy than the second photons.

## Claims

### Claim 1

A light concentrator, comprising:
a luminescent concentrator including a semiconductor material that absorbs first photons, wherein the first photons have energy greater than or equal to a threshold energy, and wherein, in response to absorbing the first photons, the semiconductor material emits second photons through a spontaneous emission process, wherein the second photons have less energy than the first photons; and
a gain medium optically coupled to the luminescent concentrator to receive and absorb the second photons, wherein the gain medium is coupled to emit third photons through a stimulated emission process in response to absorbing the second photons, and wherein the third photons have less energy than the second photons.

### Claim 2 (depends on 1)

The light concentrator of claim 1, wherein the first photons include sunlight, and wherein the threshold energy is equal to a bandgap energy of the semiconductor material.

### Claim 3 (depends on 1)

The light concentrator of claim 1, wherein a population inversion of electrons occurs in the gain medium in response to the gain medium receiving a threshold quantity of second photons.

### Claim 4 (depends on 1)

The light concentrator of claim 1, wherein the luminescent concentrator exhibits internal reflection.

### Claim 5 (depends on 1)

The light concentrator of claim 1, further comprising a reflective material disposed on a surface of the luminescent concentrator to prevent the first photons and the second photons from escaping the luminescent concentrator, and wherein the reflective material directs the first photons and the second photons into the gain medium.

### Claim 6 (depends on 1)

The light concentrator of claim 1, wherein the gain medium is disposed within the luminescent concentrator.

### Claim 7 (depends on 1)

The light concentrator of claim 1, further comprising a second luminescent concentrator including a second semiconductor material to absorb the first photons, wherein the second semiconductor material has a different density of states than the semiconductor material, and wherein the second semiconductor material emits the second photons.

### Claim 8 (depends on 1)

The light concentrator of claim 1, wherein the luminescent concentrator includes a transparent material, and the semiconductor material includes semiconductor particles disposed in the transparent material.

### Claim 9 (depends on 8)

The light concentrator of claim 8, wherein the semiconductor material includes quantum dots.

### Claim 10 (depends on 1)

The light concentrator of claim 1, wherein the gain medium is physically adhered to the luminescent concentrator.

### Claim 11

A power system, comprising:
a light concentrator including:
a luminescent concentrator including a semiconductor material that absorbs first photons, wherein the first photons have energy greater than or equal to a bandgap energy of the semiconductor material, wherein, in response to absorbing the first photons, the semiconductor material emits second photons with less energy than the first photons; and
a gain medium optically coupled to the luminescent concentrator to receive and absorb the second photons, wherein the gain medium is coupled to emit third photons through a stimulated emission process in response to absorbing the second photons, and wherein the third photons have less energy than the second photons; and
a power converter optically coupled to the gain medium to convert the third photons into another form of energy.

### Claim 12 (depends on 11)

The power system of claim 11, wherein the power converter includes a photovoltaic device optically coupled to the gain medium to convert the third photons into electrical energy.

### Claim 13 (depends on 12)

The power system of claim 12, further comprising an optical cable disposed between the photovoltaic device and the gain medium, wherein the optical cable facilitates optical coupling between the photovoltaic device and the gain medium, and wherein the optical cable transfers the third photons a distance from the gain medium to the photovoltaic device.

### Claim 14 (depends on 11)

The power system of claim 11, wherein the power converter includes power storage that stores electrical energy or thermal energy generated by the light concentrator.

### Claim 15 (depends on 11)

The power system of claim 11, further comprising a plurality of light concentrators including the light concentrator, wherein the plurality of light concentrators is coupled to the power converter.

### Claim 16 (depends on 11)

The power system of claim 11, wherein the power converter converts the third photons into chemical energy.

### Claim 17 (depends on 16)

The power system of claim 16, wherein the power converter includes power storage that stores the chemical energy.

### Claim 18

A method of light concentration, comprising:
receiving first photons with a luminescent concentrator including a semiconductor material;
absorbing the first photons with the semiconductor material, wherein the first photons have a first energy greater than or equal to a bandgap energy of the semiconductor material;
emitting second photons with the semiconductor material, wherein the second photons have a second energy that is less than the first energy;
absorbing the second photons with a gain medium, wherein electrons in the gain medium achieve population inversion after the gain medium absorbs a threshold quantity of the second photons; and
emitting third photons from the gain medium via a stimulated emission process, wherein the third photons have less energy than the second photons.

### Claim 19 (depends on 18)

The method of claim 18, wherein emitting second photons with the semiconductor material includes emitting the second photons through a spontaneous emission process.

### Claim 20 (depends on 18)

The method of claim 18, further comprising outputting the third photons to a power converter, wherein the power converter converts the third photons into electrical energy.

### Claim 21 (depends on 18)

The method of claim 18, further comprising outputting the third photons to a power converter, wherein the power converter converts the third photons into chemical energy.

### Claim 22 (depends on 18)

The method of claim 18, further comprising outputting the third photons to a laser emitter.

### Claim 23 (depends on 18)

The method of claim 18, wherein groups of photons in the third photons are coherent, in phase, and have a same polarization.