Non-perturbative generation of DUV/VUV harmonics from crystal surfaces at 108 MHz repetition rate

Seres, J.; Seres, E.; Serrat, Carles; Schumm, Thorsten

doi:10.1364/oe.26.021900

Cited by 16 publications

(15 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…6(a), the measured spectrum generated on the back surface of the sapphire substrate alone (without AlN film) is compared to the spectrum obtained when the back surface of the sapphire comprises the AlN film. As reported in previous work [25], harmonics are more intensely generated if the film is situated on the back surface. In the cavity, the -40 fs 2 dispersion compensation yields the strongest harmonics, as described above.…”

Section: Bandgap Tuning: Using Aln Film As Mhg Sourcesupporting

confidence: 80%

“…(b) The power of the generated harmonics is strongly affected by the introduced intra-cavity GDD and follows the peak intensity of the intra-cavity laser pulses. (c) Comparing to an extra-cavity setup, when the harmonics are directly generated with the output of the Ti:sapphire oscillator [25], strong increase of the 5 th harmonic power is obtained by placing the AlN sample into the enhancement cavity.…”

Section: Fig 2 (A)mentioning

confidence: 99%

See 1 more Smart Citation

All-solid-state VUV frequency comb at 160 nm using high-harmonic generation in nonlinear femtosecond enhancement cavity

Seres¹,

Seres²,

Serrat³

et al. 2019

Opt. Express

Self Cite

View full text Add to dashboard Cite

We report on the realization of a solid-state-based vacuum ultraviolet frequency comb, using multiharmonic generation in an external enhancement cavity. Optical conversions in such arrangements were so-far reported only using gaseous media. We present a theory that allows selecting the most suited solid generation medium for specific target harmonics by adapting the bandgap of the material. Consequently, we experimentally use a thin AlN film grown on a sapphire substrate to realize a compact frequency comb multi-harmonic source in the DUV/VUV spectral range. Extending our earlier VUV source [Opt. Exp. 26, 21900 (2018)] with the enhancement cavity, a sub-Watt level Ti:sapphire femtosecond frequency comb is enhanced to 24 W stored average power, its 3 rd , 5 th and 7 th harmonics are generated, and the target harmonic power at 160 nm increased by two orders of magnitude. The emerging non-linear effects in the solid medium together with suitable intra-cavity dispersion management support optimal enhancement and stable locking. To demonstrate the spectroscopic ability of the realized frequency comb, we report on the beat measurement between the 3 rd harmonic beam and a 266 nm CW laser reaching about 1 MHz accuracy.

show abstract

Section: Bandgap Tuning: Using Aln Film As Mhg Sourcesupporting

confidence: 80%

Section: Fig 2 (A)mentioning

confidence: 99%

All-solid-state VUV frequency comb at 160 nm using high-harmonic generation in nonlinear femtosecond enhancement cavity

Seres¹,

Seres²,

Serrat³

et al. 2019

Opt. Express

Self Cite

View full text Add to dashboard Cite

show abstract

“…In centro-symmetric crystals such as MgO used in this study, phase matching conditions are not met, and the observed SHG produced is due to SSHG. For example, perturbative and non-perturbative high harmonics have been generated from the surface states of solids which shows the suppression of higher harmonics in bulk material due to lack of phase matching [1]. For an in-depth theoretical and experimental treatment of SHG, we refer the reader to the following works [2][3][4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Controlling the non-linear optical properties of MgO by tailoring the electronic structure

et al. 2020

View full text Add to dashboard Cite

The study of the non-linear response of matter to high electric fields has recently encompassed harmonic generation in solids at near-infrared (NIR) driving wavelengths. Interest has been driven by the prospect of ultrafast signal processing and all-optical mapping of electron wavefunctions in solids. Engineering solid-state band structures to control the non-linear process has already been highlighted theoretically. Here, we show experimentally for the first time that second harmonic generation (SHG) can be enhanced by doping crystals of magnesium oxide (MgO) with chromium (Cr) atoms. We show that the degree of enhancement depends nonlinearly on dopant concentration. The SHG efficiency is shown to increase when Cr dopants are introduced into pure MgO. A physical picture of the effect of Cr dopants is aided by density functional theory (DFT) calculations of the electronic structure for pure and doped samples. This work shows an unambiguous enhancement of the SHG efficiency by modifying the electronic structure. The observed effects are consistent with an electronic structure that facilitates the surface induced SHG and demonstrates a minimal angular dependence. This work highlights the potential of manipulating the electronic structure of solids to control or test theories of their non-linear optical response.

show abstract

“…In this case, high conversion efficiency can be expected owing to the high electric field strength of the femtosecond laser that removes the restriction that the phase matching condition must be satisfied and dramatically expands the choice of nonlinear media. In fact, recently, new types of solid nonlinear materials for VUV generation, such as surfaces of transparent solids in the visible region [25,26] and dielectric metasurfaces [27,28], which are artificial nanostructures with sizes comparable with or smaller than the light wavelength, have been proposed and demonstrated.…”

Section: Introductionmentioning

confidence: 99%

“…where max ( ) I n is the maximum average power of generated n-th order harmonic wave,  is the n-th order nonlinear coefficient, and is the maximum electric field amplitude of the fundamental beam. To increase max ( ) F n , the value of N has been increased using an oscillator with a high MHz-order repetition rate [25,26] and the value of has been effectively enhanced using the metasurfaces owing to the effect of Mie resonances in the dielectric nanostructures [27,28]. Despite these efforts, the power of the VUV light generated from these methods are still too weak to be used for practical application, such as laser ARPES and ECD spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

Tunable third harmonic generation in the vacuum ultraviolet region using dielectric nanomembranes

et al. 2020

View full text Add to dashboard Cite

Tunable coherent light sources operating in the vacuum ultraviolet (VUV) region in 100-200-nm (6-12 eV) wavelength range have important spectroscopic applications in many research fields, including time-resolved angle-resolved photoemission spectroscopy (ARPES). Recent advances in laser technology have enabled the upconversion of visible femtosecond lasers to the vacuum and extreme ultraviolet regions. However, the complexity of their experimental setups and the scarcity of bulk nonlinear crystals for VUV generation have hampered its widespread use. Here, we propose the use of a free-standing dielectric nanomembranes as a simple and practical method for tunable VUV generation. We demonstrate that third harmonic VUV light is generated with sufficient intensity for spectroscopic applications from commercially available SiO 2 nanomemebranes of submicron thicknesses under excitation with visible femtosecond laser pulses. The submicron thickness of the nanomembranes is optimal for maximize the VUV generation efficiency and prevents self-phase modulation and spectral broadening of the fundamental beam. The observed VUV photons are up to 10 7 photons per pulse at 157 nm with 1-kHz repetition rate, corresponding to a conversion efficiency of 10 -6 . Moreover, the central VUV wavelength can be tuned in 146-190-nm wavelength range by changing the fundamental wavelength. We also explore material and thickness dependence with experiments and calculations. The presented results suggest that dielectric nanomembranes can be used as a practical nonlinear media for VUV spectroscopic applications.

show abstract

Non-perturbative generation of DUV/VUV harmonics from crystal surfaces at 108 MHz repetition rate

Cited by 16 publications

References 32 publications

All-solid-state VUV frequency comb at 160 nm using high-harmonic generation in nonlinear femtosecond enhancement cavity

All-solid-state VUV frequency comb at 160 nm using high-harmonic generation in nonlinear femtosecond enhancement cavity

Controlling the non-linear optical properties of MgO by tailoring the electronic structure

Tunable third harmonic generation in the vacuum ultraviolet region using dielectric nanomembranes

Contact Info

Product

Resources

About