Generation of 1.5 µJ single-cycle terahertz pulses by optical rectification from a large aperture ZnTe crystal

Blanchard, F.; Razzari, Luca; Bandulet, H.; Sharma, Gargi; Morandotti, Roberto; Kieffer, J. C.; Ozaki, T.; Reid, M.; Tiedje, H.F.; Haugen, H.K.; Hegmann, Frank A.

doi:10.1364/oe.15.013212

Cited by 327 publications

(154 citation statements)

References 33 publications

Supporting

Mentioning

147

Contrasting

Unclassified

Order By: Relevance

“…Fabrication costs are dominated by the substrate price, and we are able to deposit homogeneous layers on substrates with diameters as large as 20 cm (see Methods). Preliminary tests show that driving such large-area trilayers with intense laser pulses easily yields THz pulses with peak fields of several 100 kV cm -1 which exceed those obtained with more strongly pumped large-area ZnTe emitters 50 . Therefore, spintronic THz sources exhibit a high potential for enabling nonlinear-optical studies 51,52 in the difficult-to-access region between 5 and 10 THz.…”

Section: Resultsmentioning

confidence: 97%

Efficient metallic spintronic emitters of ultrabroadband terahertz radiation

Seifert¹,

Jaiswal²,

Martens³

et al. 2016

Nature Photon

727

802

View full text Add to dashboard Cite

Terahertz electromagnetic radiation is extremely useful for numerous applications such as imaging and spectroscopy. Therefore, it is highly desirable to have an efficient table-top emitter covering the 1-to-30-THz window whilst being driven by a low-cost, low-power femtosecond laser oscillator. So far, all solid-state emitters solely exploit physics related to the electron charge and deliver emission spectra with substantial gaps. Here, we take advantage of the electron spin to realize a conceptually new terahertz source which relies on tailored fundamental spintronic and photonic phenomena in magnetic metal multilayers: ultrafast photo-induced spin currents, the inverse spin-Hall effect and a broadband Fabry-Pérot resonance. Guided by an analytical model, such spintronic route offers unique possibilities for systematic optimization. We find that a 5.8-nm-thick W/CoFeB/Pt trilayer generates ultrashort pulses fully covering the 1-to-30-THz range. Our novel source outperforms laser-oscillatordriven emitters such as ZnTe(110) crystals in terms of bandwidth, terahertz-field amplitude, flexibility, scalability and cost. IntroductionThe terahertz (THz) window, loosely defined as the frequency range from 0.3 to 30 THz in the electromagnetic spectrum, is located between the realms of electronics and optics 1,2 . As this region coincides with many fundamental resonances of materials, THz radiation enables very selective spectroscopic insights into all phases of matter with high temporal 3,4 and spatial 5,6,7,8 resolution. Consequently, numerous applications in basic research 3,4 , imaging 5 and quality control 8 have emerged.To fully exploit the potential of THz radiation, energy-efficient and low-cost sources of ultrashort THz pulses are required. Most broadband table-top emitters are driven by femtosecond laser pulses that generate the required THz charge current by appropriately mixing the various optical frequencies 9,10 . Sources made from solids usually consist of semiconducting or insulating structures with naturally or artificially broken inversion symmetry. When the incident photon energy is below the semiconductor band gap, optical rectification causes a charge displacement that follows the intensity envelope of the incident pump pulse 9,10,11,12,13,14,15,16,17 . For above-band-gap excitation, the response is dominated by a photocurrent 18,19,20,21,22,23,24 with a temporally step-like onset and, thus, generally smaller bandwidth than optical rectification 9 . Apart from rare exceptions 14 , however, most semiconductors used are polar 1,2,12,13,15,16,17,21,22 and strongly attenuate THz radiation around optical phonon resonances, thereby preventing emission in the so-called Reststrahlen band located between ~1 and 15 THz.The so far most promising sources covering the full THz window are photocurrents in transient gas plasmas 9,10,25,26,27,28,29 . The downside of this appealing approach is that the underlying ionization process usually requires amplified laser pulses with high threshold energies on the order of 0....

show abstract

Section: Resultsmentioning

confidence: 97%

Efficient metallic spintronic emitters of ultrabroadband terahertz radiation

Seifert¹,

Jaiswal²,

Martens³

et al. 2016

Nature Photon

727

802

View full text Add to dashboard Cite

show abstract

“…The main limiting factor in THz generation using ZnTe is free-carrier absorption caused by two-photon absorption of the pump light, which limits pump intensity (see next Section). Even though THz energies as high as 1.5 µJ have been demonstrated by using large pump spots [76] the achieved conversion efficiency of 1.3×10 -5 was rather low. In contrast, by using LN with TPFP, THz energies of 10 µJ [90] and 30 µJ [96] have been reported with pump-to-THz energy conversion efficiencies of 5×10 -4 and 1.1×10 -3 , respectively.…”

Section: 2velocity Matching By Tilting the Pump Pulse Frontmentioning

confidence: 97%

“…4.3). Hence, the useful pump intensity is limited, which is a serious restriction in high-energy THz pulse generation [76]. The situation is similar with GaP, another semiconductor material frequently used for OR with considerably smaller FOM value.…”

Section: 1theory and Materialsmentioning

confidence: 99%

See 1 more Smart Citation

Intense ultrashort terahertz pulses: generation and applications

Hoffmann¹,

Fülöp²

2011

J. Phys. D: Appl. Phys.

332

215

View full text Add to dashboard Cite

Ultrashort terahertz pulses derived from femtosecond table-top sources have become a valuable tool for time-resolved spectroscopy during the last two decades. Until recently, the pulse energies and field strengths of these pulses have been generally too low to allow for the use as pump pulses or the study of nonlinear effects in the terahertz range. In this review article we will describe methods of generation of intense single cycle terahertz pulses with emphasis on optical rectification using the tilted-pulse-front pumping technique. We will also discuss some applications of these intense pulses in the emerging field of nonlinear terahertz spectroscopy.

show abstract

“…Previously, this detector was used for measuring the energy of near-single-cycle THz pulses with an average frequency of 0.9 THz generated by an accelerator-based source [2]. Afterwards, it was reported that the sensitivity of the Coherent pyroelectric detector at 1 THz was approximately 1.8 times less than the specified sensitivity at 1.06 lm [3], and this difference has been take into account in a following publication [7].Recently, we compared the sensitivity of the Coherent Molectron J4-05 detector with that of another widely used pyroelectric THz detector (Microtech Instruments) [3][4][5][6]. The latter detector is provided with a calibration curve of the spectral dependence of the sensitivity in the frequency range of 0.12-3 THz.…”

mentioning

confidence: 99%

Erratum to: Mobile source of high-energy single-cycle terahertz pulses

et al. 2014

View full text Add to dashboard Cite

In 2010, we reported [1] on a demonstration of a mobile source of high-energy near-single-cycle THz pulses based on a tilted pulse front optical rectification set-up, pumped by a mobile terawatt laser (Teramobile). The absolute value of the THz pulse energy was measured with a pyroelectric detector (Coherent Molectron J4-05). The company does not provide a spectral sensitivity dependence for this detector below 3.3 THz. In the reported experiments, generated THz pulses had broad spectra centred at 0.2 THz [1]. Previously, this detector was used for measuring the energy of near-single-cycle THz pulses with an average frequency of 0.9 THz generated by an accelerator-based source [2]. Afterwards, it was reported that the sensitivity of the Coherent pyroelectric detector at 1 THz was approximately 1.8 times less than the specified sensitivity at 1.06 lm [3], and this difference has been take into account in a following publication [7].Recently, we compared the sensitivity of the Coherent Molectron J4-05 detector with that of another widely used pyroelectric THz detector (Microtech Instruments) [3][4][5][6]. The latter detector is provided with a calibration curve of the spectral dependence of the sensitivity in the frequency range of 0.12-3 THz. As a result, we found that at frequencies of 0.2-0.5 THz, the Coherent Molectron J4-05 detector underestimates the THz pulse energy by a factor of about 3.5 with regard to the Microtech Instruments detector. This finding evidences an additional drop of the Coherent Molectron J4-05 detector sensitivity for THz wave frequencies below 1 THz. By this comparison, we conclude that the THz pulse energy in Ref.[1] should significantly be re-estimated, up to 175 lJ (instead of the initially published value of 50 lJ), which is to the best of our knowledge the highest energy of near-single-cycle THz pulses generated by tabletop sources.

show abstract

Generation of 1.5 µJ single-cycle terahertz pulses by optical rectification from a large aperture ZnTe crystal

Cited by 327 publications

References 33 publications

Efficient metallic spintronic emitters of ultrabroadband terahertz radiation

Efficient metallic spintronic emitters of ultrabroadband terahertz radiation

Intense ultrashort terahertz pulses: generation and applications

Erratum to: Mobile source of high-energy single-cycle terahertz pulses

Contact Info

Product

Resources

About