# US 7,609,741 B2 · Disk laser including an amplified spontaneous emission (ASE) suppression feature > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,609,741 B2 - Document ID: US7609741B2 - Status: Granted - Kind: B2 - Application number: 11/626,096 - Filed: 2007-01-23 - Published: 2008-07-24 - Granted: 2009-10-27 - Earliest claimed: 2007-01-23 - Assignees: The Boeing Company - Inventors: Jan Vetrovec - Web page: https://patentgrep.com/patent/US7609741B2 ## CPC - H01S 3/0612: {Non-homogeneous structure (H01S3/07 takes precedence)} - H01S 3/042: for solid state lasers {(H01S3/0401 takes precedence)} - H01S 3/0604: {in the form of a plate or disc} - H01S 3/0617: {having a varying composition or cross-section in a specific direction} - H01S 3/08095: {Zig-zag travelling beam through the active medium} - H01S 3/081: comprising three or more reflectors - H01S 3/09415: {the pumping beam being parallel to the lasing mode of the pumped medium, e.g. end-pumping} - H01S 2301/02: ASE (amplified spontaneous emission), noise; Reduction thereof - 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 system may include a first portion of laser host material adapted for amplification of laser radiation and a second portion of laser host material surrounding the first portion which may be adapted for suppression of ASE. The first portion of laser host material and the second portion of laser host material may be respectively doped at a different predetermined concentration of laser ions. A heat exchanger may be provided to dissipate heat from the first portion and the second portion. ## Claims ### Claim 1 A laser system, comprising: a laser disk, comprising: a front surface; a back surface opposite to the front surface; a first portion of laser host material adapted for amplification of laser radiation; and a second portion of laser host material completely surrounding the first portion of laser host material between the front surface and the back surface and adapted for suppression of ASE, wherein the first portion of laser host material and the second portion of laser host material are both doped with laser ions, each at a different predetermined concentration of laser ions; and a heat exchanger thermally coupled to the back face of the laser disk to dissipate heat from the first portion and the second portion. ### Claim 2 (depends on 1) The laser system of claim 1 wherein the first portion of laser host material comprises doping with laser ions at a first predetermined concentration for amplification of laser radiation, and wherein the second portion of laser host material comprises doping with laser ions at a second predetermined concentration for absorption of ASE. ### Claim 3 (depends on 2) The laser system of claim 2, wherein the second predetermined concentration is substantially higher than the first predetermined concentration. ### Claim 4 (depends on 2) The laser system of claim 2, wherein the laser ion comprises a quasi-3 level ion. ### Claim 5 (depends on 2) The laser system of claim 2, wherein the first portion is doped with different laser ions from the second portion. ### Claim 6 (depends on 1) The laser system of claim 1, wherein the laser host material is selected from a group comprising yttrium aluminum garnet (YAG); gadolinium gallium garnet (GGG); gadolinium scandium gallium garnet (GSGG); potassium gadolinium tungstate (KGW); potassium yttrium tungstate (KYW); fluoroapatite (FAP), lithium yttrium fluoride (YLF); phosphate laser glass; silicate laser glass; and sapphire. ### Claim 7 (depends on 1) The laser system of claim 1, wherein the first portion comprises a substantially cylindrical shape and the second portion comprises a substantially annular shape, the first portion being adapted to fit within the second portion with a substantially minimal variation in an index of refraction across an interface between an outer cylindrical face of the first portion and an inner annular face of the second portion. ### Claim 8 (depends on 1) The laser system of claim 1, wherein the first portion is substantially conically shaped and the second portion is substantially annular with a conically shaped opening adapted to receive the first portion. ### Claim 9 (depends on 1) The laser system of claim 1, further comprising a pump radiation source for directing pump radiation on the first portion of laser host material. ### Claim 10 (depends on 9) The laser system of claim 9, further comprising a pump radiation reflector to reflect the pump radiation from the first portion of laser host material back to the first portion of laser host material. ### Claim 11 (depends on 1) The laser system of claim 1, further comprising an antireflective coating formed on the front surface of at least the first portion of laser host material. ### Claim 12 (depends on 1) The laser system of claim 1, further comprising a high-reflectivity coating formed on the back surface of at least the first portion of laser host material. ### Claim 13 (depends on 1) The laser system of claim 1, wherein the first portion and the second portion are co-joined to form an optically continuous and monolithic body including a substantially minimal variation in an index of refraction across an interface between the first and second portions. ### Claim 14 (depends on 13) The laser system of claim 13, wherein the first portion and the second portion are joined by a diffusion bonding process. ### Claim 15 (depends on 1) The laser system of claim 1, further comprising a vehicle, wherein the laser system is mountable to the vehicle. ### Claim 16 A thin disk laser, comprising: a front face; a back face parallel to the front face; a central portion of laser host material doped with laser ions at a first predetermined concentration for amplification of laser radiation; and an edge portion of laser host material completely surrounding the central portion between the front face and the back face and doped with laser ions at a second predetermined concentration for suppression of ASE, wherein the second predetermined concentration is substantially higher than the first predetermined concentration. ### Claim 17 (depends on 16) The thin laser disk of claim 16, wherein the central portion is substantially cylindrical and the edge portion is substantially annular, and wherein the central portion is adapted to fit within the edge portion to form an interface between an outer cylindrical face of the central portion and an inner annular face of the edge portion with a substantially minimal variation in an index of refraction across the interface. ### Claim 18 (depends on 16) The thin disk laser of claim 16, wherein the central portion is substantially conical and the edge portion includes a substantially conically shaped opening formed therein to received the central portion to form an interface between an outer conical face of the central portion and an inner conical face of the edge portion with a substantially minimal variation in an index of refraction across the interface. ### Claim 19 (depends on 16) The thin disk laser of claim 16, wherein the central portion and the edge portion are joined together to form an optically continuous and monolithic body with substantially minimal variation in an index of refraction across an interface between the central and edge portions. ### Claim 20 (depends on 16) The thin disk laser of claim 16, further comprising heat dissipation means for receiving heat from the central and edge portions. ### Claim 21 (depends on 16) The thin disk laser of claim 16, further comprising: an antireflective coating formed on the front face of at least the central portion of the laser host material to pass laser radiation into the laser host material; and a high-reflective coating formed on the back face of at least the central portion of the laser host material to reflect any laser radiation. ### Claim 22 (depends on 1) The laser system of claim 1, wherein the predetermined doping concentration of the second portion of laser host material is about 10 percent to more than about 50 percent higher than the predetermined doping concentration of the first portion of laser host material. ### Claim 23 (depends on 1) The laser system of claim 1, wherein the first portion of laser host material comprises the predetermined doping concentration of about a 10 percent atomic concentration of laser ions and the second portion of laser host material comprises the predetermined doping concentration of about 15% atomic concentration of laser ions. ### Claim 24 (depends on 1) The laser system of claim 1, wherein the first portion of laser host material and the second portion of laser host material are formed separately for doping at the different predetermined concentrations of laser ions and wherein the first portion of laser host material is inserted within the second portion of laser host material after the first and second portions are doped at the different predetermined concentrations of laser ions.