Narrowband terahertz generation with chirped-and-delayed laser pulses in periodically poled lithium niobate

Ahr, Frederike; Jolly, Spencer W.; Matlis, Nicholas H.; Carbajo, Sergio; Kroh, Tobias; Ravi, Koustuban; Schimpf, Damian N.; Schulte, Jan; Ishizuki, Hideki; Taira, Takunori; Maier, Andreas R.; Kärtner, Franz X.

doi:10.1364/ol.42.002118

Cited by 70 publications

(54 citation statements)

References 20 publications

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“…Cryogenic cooling allows the use of long crystals and cascading does not lead to break-up of the driver pulses as in the TPFT case due to collinear interaction of the waves [4]. DFG using highenergy broadband Ti:Sappire pulses and the chirp and delay method to match the difference frequency to the quasiphase matching period resulted in 40 µJ pulses at 0.5 THz and 260 ps duration [5]. The use of large aperture crystals fabricated by the Taira group and linearization of the difference frequency between the chirped and delayed pulses lead to further improvements by more than an order of magnitude to produce 460 µJ of THz radiation with about 460 mJ of laser pulses [6].…”

Section: High Energy Thz Generationmentioning

confidence: 99%

THz Driven Accelerators and X-ray Sources

Kärtner

2018

Conference on Lasers and Electro-Optics

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Approaches towards a linear THz accelerator technology are discussed. Theoretical and first experimental results on laser based high energy THz generation, guns, accelerators as well as compact X-ray sources based on these devices are presented. IntroductionToday, high brightness and highly relativistic electron beams are generated by circular or linear accelerators (LINAC) typically operating with 1-3 GHz accelerating frequencies and approaches towards X-band frequencies in the 10 GHz range are maturing. The achievable accelerating gradients are limited by field emission from cavity walls influenced by pulsed heating to several tens of MV/m in the case of low frequencies and up to 100 MV/m in the case of X-band frequencies. Short electron bunches are typically created by photoemission from the cathode in the presence of a strongly accelerating field followed by bunch compression. Low charge bunches, 1-10 pC, may be compressed to durations down to 3 -10 µm (or 10 -30 fs in pulse duration). At a given accelerating field strength and RF frequency, compression is limited by space charge. With higher operating frequency, higher gradients in the accelerating electric field arise which enhances velocity bunching and leads to the generation of shorter electron bunches. These short electron bunches can be used for ultrafast electron diffraction or intense X-ray production. Choosing an operating frequency of the accelerator in the THz range, i.e. here 0.1 -0.5 THz and using multi-cycle to single-cycle pulses, accelerating fields in the 0.3 to 1 GV/m range are sustainable and bunch compression to the sub-femtosecond level of significant charge on the order of ~1 pC becomes possible. To drive electron guns and accelerators high-energy single-cycle and multi-cylce THz pulses in the mJ and tens of mJ range, respectively, are necessary. Here, we discuss approaches towards this goal and results achieved sofar.

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Section: High Energy Thz Generationmentioning

confidence: 99%

THz Driven Accelerators and X-ray Sources

Kärtner

2018

Conference on Lasers and Electro-Optics

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“…Although chirp-and-delay experiments have previously been implemented in various formats, it has only recently been applied to periodically-poled crystals by our group [27], resulting in a new record in optically generated multi-cycle THz of 40 µJ. This work, which was driven by high-energy Ti:Sapphire pulses at low repetition rates and employed cryogenic cooling to reduce THz absorption in periodically-poled Mg-doped lithium niobate (PP Mg:LN), has recently been extended by increasing laser pulse energies and crystal apertures as well as by tuning the spectral phase of the chirped pulse pair.…”

Section: Chirp-and-delaymentioning

confidence: 99%

Frequency-shifted sources for terahertz-driven linear electron acceleration

Hemmer

Cirmi

Ravi

et al. 2018

Nonlinear Frequency Generation and Conversion: Materials and Devices XVII

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The generation of THz-frequency radiation via nonlinear parametric frequency down-conversion has long been driven by the spectroscopy and imaging communities. As a result, little efforts have been undertaken toward the generation of high energy THz-frequency pulses. THz-frequency radiation has however recently been identified has a promising driver for strong-field physics and an emerging generation of compact particle accelerators. These accelerators require THzfrequency pulses with energies in the multi-millijoule range therefore demanding orders of magnitude improvements from the current state-of-the-art. Much can be gained by improving the intrinsically low efficiency of the down-conversion process while still resorting to existing state-of-the-art lasers. However, the fundamental Manley-Rowe limit caps the efficiency of parametric downconversion from 1-µm wavelength lasers to sub-THz frequency to the sub-percent range. We present methods that promise boosting the THz radiation yield obtained via parametric down-conversion beyond the Manley-Rowe limit. Our method relies on cascaded nonlinear three-wave mixing between two spectrally neighboring laser pulses in periodically poled Lithium Niobate. Owing to favorable phase-matching, the down-conversion process avalanches, resulting in spectral broadening in the optical domain. This allows in-situ coherent multiplexing of multiple parametric down-conversion stages within a single device and boosting the efficiency of the process beyond the ManleyRowe limit. We experimentally demonstrated the concept using either broadband, spectrally chirped optical pulses from a Joule-class laser or using two narrowband lasers with neighboring wavelengths. Experimental results are backed by numerical simulations that predict conversion efficiencies from 1 µm to sub-THz radiation in the multi-percent range.

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“…The large area PPLN crystals with a cross section 3 mm × 3 mm are commercially available, and even a crystal with dimensions 1 cm × 1.5 cm was recently used for THz generation [13]. The ability to significantly reduce THz-waves absorption in PPLN crystal by cryogenic cooling makes it possible to use crystals with a length of about 2-3 cm [13,14]. Therefore, investigations of alternative methods for nearly single-cycle broadband THz pulse generation in domain-engineered PPLN crystals are interesting.…”

Section: Introductionmentioning

confidence: 99%

Nearly Single-Cycle Terahertz Pulse Generation in Aperiodically Poled Lithium Niobate

Avetisyan

Tonouchi

2019

Photonics

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In the present work, an opportunity of nearly single-cycle THz pulse generation in aperiodically poled lithium niobate (APPLN) crystal is studied. A radiating antenna model is used to simulate the THz generation from chirped APPLN crystal pumped by a sequence of femtosecond laser pulses with chirped delays (m = 1, 2, 3 . . . ) between adjacent pulses. It is shown that by appropriately choosing ∆t m , it is possible to obtain temporal overlap of all THz pulses generated from positive (or negative) domains. This results in the formation of a nearly single-cycle THz pulse if the chirp rate of domain length δ in the crystal is sufficiently large. In the opposite case, a few cycle THz pulses are generated with the number of the cycles depending on δ. The closed-form expression for the THz pulse form is obtained. The peak THz electric field strength of 0.3 MV/cm is predicted for APPLN crystal pumped by a sequence of laser pulses with peak intensities of the separate pulse in the sequence of about 20 GW/cm 2 . By focusing the THz beam and increasing the pump power, the field strength can reach values in the order of few MV/cm.

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Narrowband terahertz generation with chirped-and-delayed laser pulses in periodically poled lithium niobate

Cited by 70 publications

References 20 publications

THz Driven Accelerators and X-ray Sources

THz Driven Accelerators and X-ray Sources

Frequency-shifted sources for terahertz-driven linear electron acceleration

Nearly Single-Cycle Terahertz Pulse Generation in Aperiodically Poled Lithium Niobate

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