@article{329d7b5c23634235a80dc839b48d380f,
title = "Investigation of second- and third-harmonic generation in few-layer gallium selenide by multiphoton microscopy",
abstract = "Gallium selenide (GaSe) is a layered semiconductor and a well-known nonlinear optical crystal. The discovery of graphene has created a new vast research field focusing on two-dimensional materials. We report on the nonlinear optical properties of few-layer GaSe using multiphoton microscopy. Both second- and third-harmonic generation from few-layer GaSe flakes were observed. Unexpectedly, even the peak at the wavelength of 390 nm, corresponding to the fourth-harmonic generation or the sum frequency generation from third-harmonic generation and pump light, was detected during the spectral measurements in thin GaSe flakes.",
author = "Lasse Karvonen and Antti S{\"a}yn{\"a}tjoki and Soroush Mehravar and Rodriguez, \{Raul D.\} and Susanne Hartmann and Zahn, \{Dietrich R.T.\} and Seppo Honkanen and Norwood, \{Robert A.\} and N. Peyghambarian and Khanh Kieu and Harri Lipsanen and Juha Riikonen",
note = "Funding Information: The work is financed by the Academy of Finland, TEKES ‒ the Finnish Funding Agency for Technology and Innovation, the European Union Seventh Framework Programme under grant agreement n°604391 Graphene Flagship, the Graduate School of Modern Optics and Photonics, the Finnish Foundation for Technology Promotion, and the Walter Ahlstr{\"o}m Foundation. We also acknowledge the provision of technical facilities of the Micronova, Nanofabrication Centre of Aalto University. We would also like to acknowledge the CIAN NSF ERC under grant EEC-0812072. University of Arizona contributors would like to acknowledge the support of the AFOSR COMAS MURI (FA9550–10–1–0558), the ONR NECom MURI, the CIAN NSF ERC under grant EEC-0812072, and TRIF Photonics funding from the state of Arizona. RDR acknowledges financial support from the German Science Foundation DFG, Research Unit SMINT FOR1317. RDR and SHa greatly appreciate and acknowledge Evgeniya Sheremet for fruitful discussions. We thank Santos A. Lopez-Rivera for the growth of GaSe single crystals.",
year = "2015",
month = may,
day = "19",
doi = "10.1038/srep10334",
language = "English (US)",
volume = "5",
journal = "Scientific reports",
issn = "2045-2322",
publisher = "Nature Research",
}