Method and apparatus for generating THz radiation

Patent metadata

Field	Value
Publication number	US-10095083-B2
Application number	US-201715463717-A
Country	US
Kind code	B2
Filing date	Mar 20, 2017
Priority date	Mar 21, 2016
Publication date	Oct 9, 2018
Grant date	Oct 9, 2018

Abstract

A method of generating THz radiation includes the steps of generating optical input radiation with an input radiation source device ( 10 ), irradiating a first conversion crystal device ( 30 ) with the optical input radiation, wherein the first conversion crystal device ( 30 ) is arranged in a single pass configuration, and generating the THz radiation having a THz frequency in the first conversion crystal device ( 30 ) in response to the optical input radiation by an optical-to-THz-conversion process, wherein a multi-line frequency spectrum is provided by the optical input radiation in the first conversion crystal device ( 30 ), and the optical-to-THz-conversion process includes cascaded difference frequency generation using the multi-line frequency spectrum. Furthermore, a THz source apparatus being configured for generating THz radiation and applications thereof are described.

First claim

What is claimed is:

1. A method of generating THz radiation, comprising the steps of:
generating optical input radiation with an input radiation source device, wherein the optical input radiation generated with the input radiation source device comprises a first radiation component and a second radiation component including optical frequencies separated by the THz frequency of the THz radiation to be generated,
irradiating a first conversion crystal device with the optical input radiation, wherein the first conversion crystal device is arranged in a single pass configuration, wherein the first radiation component and the second radiation component irradiate the first conversion crystal device with a mutual spatial and temporal overlap along a beam path through the first conversion crystal device, and
generating the THz radiation having a THz frequency in the first conversion crystal device in response to the optical input radiation by an optical-to-THz-conversion process, wherein
a multi-line frequency spectrum is provided by the optical input radiation in the first conversion crystal device, wherein the multi-line frequency spectrum is provided by beating frequencies derived from the optical frequencies of the first and second radiation components, and
the optical-to-THz-conversion process includes cascaded difference frequency generation using the multi-line frequency spectrum.

2. The method according to claim 1 , wherein the first radiation component and the second radiation component irradiate the first conversion crystal device with a collinear geometry.

3. The method according to claim 1 , wherein the input radiation source device has two laser sources being locked to each other and generating the first radiation component and the second radiation component, respectively, the laser sources including:
two continuous wave laser sources,
two quasi-continuous wave laser sources emitting pulses having a duration in a range from 100 ps to 10 ns,
one continuous wave laser source and one quasi-continuous wave laser source,
two pulse laser sources emitting pulses having a transform limited duration in a range from 10 fs to 100 ps,
one broadband chirped pulse laser source, combined with a pulse stretcher, and one pulse laser source, combined with a relative delay unit, or
two broadband chirped pulse laser sources, combined with a relative delay unit.

4. The method according to claim 3 , wherein the laser sources generate the first radiation component and the second radiation component with different output power, wherein a fraction of a weaker output power to a stronger output power is larger than 0.01% and smaller than 50%.

5. The method according to claim 1 , wherein the first conversion crystal device has at least one of the features
the first conversion crystal device is configured for quasi phase matching by bonding of wafers with periodically inverted crystal device axes or by stacking several smaller periodically poled crystal devices,
the first conversion crystal device is configured for quasi phase matching with gradually varying quasi phase matching period along a beam path,
the first conversion crystal device is configured for regular phase matching being phase-matched for the THz frequency of the THz radiation to be generated,
the first conversion crystal device comprises a plurality of crystal layers being arranged at Brewsters's angle relative to the optical input radiation,
the first conversion crystal device comprises a bulk crystal or a periodically poled crystal,
the first conversion crystal device comprises congruent Lithium Niobate (cLN), Stoichiometric Lithium Niobate (sLN), Congruent Lithium Tantalate (cLT), Stoichiometric Lithium Tantalate (sLT), Potassium Titanyl Phosphate (KTP), potassium titanyl arsenate, Zinc Germanium Phosphide (ZGP), Cadmium Silicon Phosphide (CdSiP 2 ), or Gallium Phosphide (GaP),
the first conversion crystal device includes at least one dopant, and
the first conversion crystal device has a beam path length of at least one of at least 5 mm and at most 10 cm.

6. The method of claim 1 , wherein the THz radiation is used for
driving high energy terahertz guns and electron accelerators for coherent X-ray generation or for imaging and medical therapy,
imaging,
coherent diffractive imaging,
spectroscopy,
detecting explosives,
small angle X-ray scattering,
THz or Optical pump and X-ray probe time resolved spectroscopy,
X-ray pump and X-ray probe time resolved spectroscopy,
directional wireless communication,
radar technique,
driving of highly correlated quantum systems into new phases,
driving of quantum information devices with transitions in the THz range, and
an electromagnetic undulator.

7. A method of generating THz radiation, comprising the steps of:
generating optical input radiation with an input radiation source device, wherein the optical input radiation generated with the input radiation source device comprises a first radiation component including an optical frequency and a second radiation component including the THz frequency of the THz radiation to be generated,
irradiating a first conversion crystal device with the optical input radiation, wherein the first conversion crystal device is arranged in a single pass configuration, wherein the first radiation component and the second radiation component irradiate the first conversion crystal device with a mutual spatial and temporal overlap along a beam path through the first conversion crystal device, and
generating the THz radiation having a THz frequency in the first conversion crystal device in response to the optical input radiation by an optical-to-THz-conversion process, wherein
a multi-line frequency spectrum is provided by the optical input radiation in the first conversion crystal device, wherein the multi-line frequency spectrum is provided by beating frequencies derived from the optical frequency of the first radiation component and the THz frequency of the second radiation component, and
the optical-to-THz-conversion process includes cascaded difference frequency generation using the multi-line frequency spectrum.

8. The method according to claim 7 , wherein the second radiation component having the THz frequency is generated by
optical rectification of a single ultrashort optical pulse in a pump conversion crystal device,
cascaded parametric amplification using the first and second radiation components, or
optical rectification of a sequence of multiple pulses in a pump first conversion crystal device.

9. A method of generating THz radiation, comprising the steps of:
generating optical input radiation with an input radiation source device, wherein the optical input radiation generated with the input radiation source device comprises a sequence of optical laser pulses having a temporal separation (Δt) equal to an integer multiple of a reciprocal of the THz frequency of the THz radiation to be generated (Δt=N·1/f THz , N=1, 2, . . . ),
irradiating a first conversion crystal device with the optical input radiation, wherein the first conversion crystal device is arranged in a single pass configuration, and
generating the THz radiation having a THz frequency in the first conversion crystal device in response to the optical input radiation by an optical-to-THz-conversion process, wherein
a multi-line frequency spectrum is provided by the optical input radiation in the first conversion crystal device, wherein the multi-line frequency spectrum is directly provided by the optical input radiation, and
the optical-to-THz-conversion process includes cascaded difference frequency generation using the multi-line frequency spectrum.

10. The method according to c

Assignees

• Deutsches Elektronen Synchrotron Desy
• Massachusetts Institute Of Tech Mit
• Massachusetts Inst Technology

Inventors

• Kaertner Franz X
• Barre Damian N
• Hemmer Michael
• Cirmi Giovanni
• Muecke Oliver D
• ROSSI Giulio Maria
• Fallahi Arya
• Matlis Nicholas H
• Zapata Luis E
• RAVI Koustuban
• Reichert Fabian

Classifications

• G02F2001/392

  Physics · mapped topic

• G02F1/3551 Primary

  Crystals · CPC title

• G02F1/353

  Frequency conversion, i.e. wherein a light beam is generated with frequency components different from those of the incident light beams · CPC title

• G02F1/3534

  Three-wave interaction, e.g. sum-difference frequency generation (G02F1/3532 takes precedence) · CPC title

• G02F1/3558

  Poled materials, e.g. with periodic poling; Fabrication of domain inverted structures, e.g. for quasi-phase-matching [QPM] · CPC title