# US 7,412,127 B2 · Photonic crystal reflectors/filters and displacement sensing applications > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,412,127 B2 - Document ID: US7412127B2 - Status: Granted - Kind: B2 - Application number: 11/464,781 - Filed: 2006-08-15 - Published: 2006-12-14 - Granted: 2008-08-12 - Earliest claimed: 2003-10-08 - Assignees: The Board of Trustees of the Leland Stanford Junior University - Inventors: Wonjoo Suh; Mehmet Fatih Yanik; Olav Solgaard; Shanhui Fan - Web page: https://patentgrep.com/patent/US7412127B2 ## CPC - G02B 6/1225: {comprising photonic band-gap structures or photonic lattices} - B82Y 20/00: Nanooptics, e.g. quantum optics or photonic crystals - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES ## Abstract We introduce a mechanically tunable photonic crystal structure consisting of coupled photonic crystal slabs. Using both analytic theory, and first-principles finite-difference time-domain simulations, we demonstrate that the transmission and reflection coefficients for light normally incident upon such structures can be highly sensitive to nano-scale variations in the spacing between the slabs. Moreover, by specifically configuring the photonic crystal structures, the high sensitivity can be preserved in spite of significant fabrication-related disorders. We expect such a structure to play important roles in micro-mechanically tunable optical sensors and filters. ## Claims ### Claim 1 An apparatus comprising at least one photonic crystal and a reflector adjacent to one another, each of said crystals comprising a block of dielectric material with one or two dimensionally periodic index contrast introduced into the dielectric material, wherein the at least one photonic crystal and the reflector are placed so that they form an optical cavity. ### Claim 2 (depends on 1) The apparatus of claim 1, further comprising a device controlling a distance between the crystal and the reflector. ### Claim 3 (depends on 2) The apparatus of claim 2, wherein the device controls said distance to adjust the wavelength of radiation transmitted or reflected by the at least one crystal. ### Claim 4 (depends on 2) The apparatus of claim 2, further comprising a detector detecting radiation transmitted or reflected by the at least one crystal to provide a signal indicative of said distance. ### Claim 5 (depends on 1) The apparatus of claim 1, further comprising a device controlling a lateral shift or relative rotation between the at least one crystal and the reflector. ### Claim 6 (depends on 5) The apparatus of claim 5, further comprising a detector detecting radiation transmitted or reflected by the at least one crystal to provide a signal indicative of said lateral shift or relative rotation. ### Claim 7 (depends on 1) The apparatus of claim 1, wherein said at least one crystal defines therein an array of air holes. ### Claim 8 (depends on 7) The apparatus of claim 7, wherein the array of holes in said at least one crystal has a periodicity a, said holes in such array having dimensions of at least about 0.2 a. ### Claim 9 (depends on 1) The apparatus of claim 1, wherein said at least one crystal has a background reflectivity of at least about 0.5. ### Claim 10 An optical apparatus comprising: at least one photonic crystal and a reflective medium adjacent to one another, said at least one crystal comprising a block of dielectric material with one or two dimensionally periodic index contrast introduced into the dielectric material; and a device controlling a distance between the at least one crystal and the reflective medium to adjust the wavelengths of radiation transmitted or reflected by the crystal. ### Claim 11 (depends on 10) The apparatus of claim 10, further comprising a detector detecting radiation transmitted or reflected by the at least one crystal to provide a signal indicative of said distance. ### Claim 12 (depends on 10) The apparatus of claim 10, wherein the at least one crystal defines therein an array of air holes. ### Claim 13 (depends on 12) The apparatus of claim 12, wherein the array of holes in at least said at least one crystal has a periodicity a, said holes in such array having dimensions of at least about 0.2 a. ### Claim 14 (depends on 10) The apparatus of claim 10, wherein said at least one crystal has a background reflectivity of at least about 0.5. ### Claim 15 A method controlling optical characteristics of an optical device, comprising: placing at least one photonic crystal and a reflective medium adjacent to one another, said at least one crystal comprising a block of dielectric material with one or two dimensionally periodic index contrast introduced into the dielectric material, said controlling a distance between, or a lateral shift or relative rotation between, the crystal and the reflective medium to adjust the wavelengths of radiation transmitted or reflected by the at least one crystal. ### Claim 16 (depends on 15) The method of claim 15, further comprising detecting radiation transmitted or reflected by the at least one crystal to provide a signal indicative of said distance or lateral shift. ### Claim 17 An optical apparatus comprising: two structures adjacent to one another, at least one of said structures comprising a dielectric material with one or two dimensional index contrast introduced into the dielectric material; and a device controlling a distance between the structures to adjust the wavelength of radiation transmitted or reflected by the structures. ### Claim 18 An apparatus comprising at least two photonic crystals adjacent to one another, each of said crystals comprising a block of dielectric material with one or two dimensionally periodic index contrast introduced into the dielectric material, wherein the at least two photonic crystals are placed so that they form an optical cavity. ### Claim 19 (depends on 18) The apparatus of claim 18, further comprising a device controlling a distance between the at least two crystals. ### Claim 20 (depends on 19) The apparatus of claim 19, wherein the device controls said distance to adjust the wavelength of radiation transmitted or reflected by at least one of the crystals. ### Claim 21 (depends on 18) The apparatus of claim 18, further comprising a detector detecting radiation transmitted or reflected by at least one of the crystals to provide a signal indicative of said distance. ### Claim 22 (depends on 18) The apparatus of claim 18, further comprising a device controlling a lateral shift or relative rotation between the at least two crystals. ### Claim 23 (depends on 22) The apparatus of claim 22, further comprising a detector detecting radiation transmitted or reflected by at least one of the crystals to provide a signal indicative of said lateral shift or relative rotation. ### Claim 24 (depends on 18) The apparatus of claim 18, wherein at least one of the crystals defines therein an array of air holes. ### Claim 25 (depends on 24) The apparatus of claim 24, wherein the array of holes in said at least one crystal has a periodicity a, said holes in such array having dimensions of at least about 0.2 a. ### Claim 26 (depends on 18) The apparatus of claim 18, wherein at least one of the crystals has a background reflectivity of at least about 0.5.