# US 2013/0154611 A1 · Chirped pulse frequency-domain comb for spectroscopy > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0154611 A1 - Document ID: US20130154611A1 - Status: Published application - Kind: A1 - Application number: 13/704,483 - Filed: 2011-06-17 - Published: 2013-06-20 - Earliest claimed: 2010-06-17 - Assignees: University of Virginia Patent Foundation - Inventors: Brooks Hart Pate; Kevin K. Lehmann - Web page: https://patentgrep.com/patent/US20130154611A1 ## CPC - G01N 21/3586: by Terahertz time domain spectroscopy [THz-TDS] - G01J 3/10: Arrangements of light sources specially adapted for spectrometry or colorimetry - G01J 3/4338: {Frequency modulated spectrometry} - G01N 22/00: Investigating or analysing materials by the use of microwaves or radio waves, i.e. electromagnetic waves with a wavelength of one millimetre or more (G01N3/00 - G01N17/00, G01N24/00 take precedence) - G01J 3/44: Raman spectrometry; Scattering spectrometry {; Fluorescence spectrometry} - G01N 21/31: Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry {(G01N21/72 takes precedence)} - G01N 21/62: Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light - G01N 21/67: using electric arcs or discharges - G01N 21/69: specially adapted for fluids {, e.g. molten metal} - H01S 3/0057: {Temporal shaping, e.g. pulse compression, frequency chirping (soliton generation and propagation G02F1/3513, H01S3/063 and H01S3/108)} - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) - G01J: MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY (light sources F21, H01J, H01K, H05B; investigating properties of materials by optical means G01N) - 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 pulse train comprising chirped pulses of electromagnetic energy can be used to excite a sample, such as for spectroscopic analysis. The respective chirped pulses can include a frequency sweep across a first specified bandwidth during a respective chirped pulse duration, the respective chirped pulse duration establishing a first frequency-domain comb peak separation. A width of a frequency-domain comb peak can be established at least in part by a total duration of the pulse train, and a bandwidth of the first frequency-domain comb can be determined at least in part by the first specified bandwidth of the frequency sweep of the respective chirped pulses. ## Claims ### Claim 1 A method, comprising: generating a pulse train comprising chirped pulses of electromagnetic energy, the respective chirped pulses including a frequency sweep across a first specified bandwidth during a respective chirped pulse duration, the respective chirped pulse duration establishing a first frequency-domain comb peak separation; and exciting a sample using the pulse train; wherein a width of a frequency-domain comb peak is established at least in part by a total duration of the pulse train; and wherein a bandwidth of a first frequency-domain comb is determined at least in part by the first specified bandwidth of the frequency sweep of the respective chirped pulses. ### Claim 2 (depends on 1) The method of claim 1, wherein the pulse train comprises chirped pulses respectively sweeping across a first range of frequencies corresponding to the first specified bandwidth, and wherein the method comprises: upconverting the pulse train to a higher second range of frequencies; frequency multiplying the pulse train to establish a wider second specified bandwidth of the first frequency-domain comb; and wherein the exciting a sample using the pulse train comprises exciting the sample using the upconverted and frequency multiplied pulse train. ### Claim 3 (depends on 1) The method of claim 1, wherein generating the pulse train includes applying a specified time-domain window to shape one or more of the pulse train or respective chirped pulses. ### Claim 4 (depends on 1) The method of claim 1, wherein the generating the pulse train includes using an arbitrary waveform generator (AWG). ### Claim 5 (depends on 1) The method of claim 1, comprising: obtaining a time-domain response from the sample in response to the excitation of the sample; and mixing the time-domain response with a second time-domain signal corresponding to a second frequency-domain comb, the second frequency-domain comb including a comb peak separation that is larger than the first frequency-domain comb peak separation. ### Claim 6 (depends on 5) The method of claim 5, wherein the mixing the time-domain response with a second time-domain signal includes generating a bandwidth-compressed response including interleaved frequency-domain information corresponding to the time-domain response of the sample. ### Claim 7 (depends on 5) The method of claim 5, comprising transforming the time-domain response to obtain one or more of frequency-domain magnitude or phase information corresponding to the second, higher range of frequencies and the wider second specified bandwidth of the first frequency-domain comb. ### Claim 8 (depends on 7) The method of claim 7, comprising determining a characteristic of the sample using the magnitude or phase information. ### Claim 9 (depends on 1) The method of claim 1, comprising generating a specified time-domain phase offset to successive chirped pulses included in the pulse train to establish a specified frequency shift of the frequency-domain comb. ### Claim 10 (depends on 9) The method of claim 9, comprising generating the specified time-domain phase offset to establish the second frequency-domain comb, the second frequency-domain comb including comb peaks located between the locations of the frequency-domain comb peaks of the first frequency-domain comb. ### Claim 11 An apparatus, comprising: a waveform generator circuit configured to generate a pulse train comprising chirped pulses of electromagnetic energy to excite a sample, the respective chirped pulses including a frequency sweep across a first specified bandwidth during a respective chirped pulse duration, the respective chirped pulse duration establishing a first frequency-domain comb peak separation; wherein a width of a frequency-domain comb peak is established at least in part by a total duration of the pulse train; and wherein a bandwidth of a first frequency-domain comb is determined at least in part by the first specified bandwidth of the respective chirped pulses. ### Claim 12 (depends on 11) The apparatus of claim 11, wherein the pulse train comprises chirped pulses respectively sweeping across a first range of frequencies corresponding to the first specified bandwidth, and wherein the apparatus comprises: a first mixer circuit configured to upconvert the pulse train to a higher second range of frequencies; and a frequency multiplier configured to multiply the frequency of the pulse train to establish a wider second specified bandwidth of the first frequency-domain comb in the higher second range of frequencies to excite the sample. ### Claim 13 (depends on 11) The apparatus of claim 11, wherein the pulse train includes a specified time-domain window to shape one or more of the pulse train or respective chirped pulses. ### Claim 14 (depends on 11) The apparatus of claim 11, comprising a detector configured to obtain a time-domain response from the sample in response to the excitation of the sample. ### Claim 15 (depends on 11) The apparatus of claim 11, comprising: a detector configured to obtain a time-domain response from the sample in response to the excitation of the sample; and a second mixer circuit configured to mix the time-domain response with a second time-domain signal corresponding to a second frequency-domain comb, the second frequency-domain comb including a comb peak separation that is larger than the first frequency-domain comb peak separation. ### Claim 16 (depends on 15) The apparatus of claim 15, wherein the second mixer circuit is configured to generate a bandwidth-compressed response including interleaved frequency-domain information corresponding to the time-domain response of the sample. ### Claim 17 (depends on 15) The apparatus of claim 15, comprising a signal processor circuit configured to transform the time-domain response to obtain one or more of frequency-domain magnitude or phase information corresponding to the second, higher range of frequencies and the wider second specified bandwidth of the first frequency-domain comb. ### Claim 18 (depends on 17) The apparatus of claim 17, wherein the signal processor circuit is configured to determine a characteristic of a sample using the magnitude or phase information. ### Claim 19 (depends on 11) The apparatus of claim 11, wherein the waveform generator circuit is configured to generate a specified time-domain phase offset to successive chirped pulses included in the pulse train to establish a specified frequency shift of the frequency-domain comb. ### Claim 20 (depends on 19) The apparatus of claim 19, wherein the waveform generator is configured to generate the specified time-domain phase offset to establish the second frequency-domain comb, the second frequency-domain comb including comb peaks located between the locations of the frequency-domain comb peaks of the first frequency-domain comb. ### Claim 21 An apparatus, comprising: means for generating a pulse train comprising chirped pulses of electromagnetic energy to excite a sample, the respective chirped pulses including a frequency sweep across a first specified bandwidth during a respective chirped pulse duration, the respective chirped pulse duration establishing a first frequency-domain comb peak separation; and wherein a width of a frequency-domain comb peak is established at least in part by a total duration of the pulse train; and wherein a bandwidth of a first frequency-domain comb is determined at least in part by the first specified bandwidth of the frequency sweep of the respective chirped pulses. ### Claim 22 (depends on 21) The apparatus of claim 21, wherein the pulse train comprises chirped pulses respectively sweeping across a first range of frequencies corresponding to the first specified bandwidth, and wherein the apparatus comprises: means for upconverting the pulse train to a higher second range of frequencies; and means to multiply the frequency of the pulse train to establish a wider second specified bandwidth of the first frequency-domain comb in the higher second range of frequencies to excite the sample. ### Claim 23 (depends on 21) The apparatus of claim 21, comprising: means for obtaining a time-domain response of the sample; means for providing a bandwidth-compressed response including interleaved frequency-domain information corresponding to the time-domain response of the sample.