Na{sub 2}Ge{sub 2}Se{sub 5}: A highly nonlinear optical material

Journal Article · Thu Nov 15 04:00:00 EST 2012 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/J.JSSC.2012.05.038· OSTI ID:22149900

Chung, In ^[1]; Song, Jung-Hwan; Jang, Joon I.; Freeman, Arthur J. ^[2]

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1. Department of Chemistry, Northwestern University, Evanston, IL 60208 (United States)
2. Department of Physics and Astronomy, Northwestern University, Evanston, IL 60208 (United States)

We report an integrated experimental and theoretical study of the two-dimensional polar selenogermanate compound Na{sub 2}Ge{sub 2}Se{sub 5}, which exhibits strong nonlinear optical (NLO) second harmonic generation response in the visible and infrared region. The compound is type-I phase-matchable with a large SHG coefficient {chi}{sup (2)} Almost-Equal-To 290 pm V{sup -1}, which is the second highest among the phase-matchable NLO materials. It also performs as an NLO frequency mixer to produce radiation via difference frequency generation. The compound is optically transparent from the visible (0.521 {mu}m) to the far IR (18.2 {mu}m) and melts congruently. Ab initio density functional theory band structure calculations show that the unusually large second-order optical nonlinearity is attributed to the two-dimensional character of the crystal structure. Raman, IR and optical absorption spectroscopy, differential thermal analysis, NLO properties of derivatives of Na{sub 2}Ge{sub 2}Se{sub 4.55}Te{sub 0.45} and Na{sub 2}Ge{sub 1.64}Sn{sub 0.36}Se{sub 5} and thermal expansion behavior studies are also reported. - Graphical Abstract: Na{sub 2}Ge{sub 2}Se{sub 5} is a new second-order nonlinear optical material for IR applications. It is type-I phase-matchable with a large SHG coefficient {chi}{sup (2)} Almost-Equal-To 290 pm V{sup -1}, which is the second largest among the phase-matchable NLO materials. Highlights: Black-Right-Pointing-Pointer Na{sub 2}Ge{sub 2}Se{sub 5} is a new second-order nonlinear optical material for IR applications. Black-Right-Pointing-Pointer It is type-I phase-matchable. Black-Right-Pointing-Pointer Its SHG coefficient {chi}{sup (2)} Almost-Equal-To 290 pm V{sup -1} is the second largest among the phase-matchable NLO materials. Black-Right-Pointing-Pointer Its DFG performance allows the development of a multiple IR frequency source with tunability. Black-Right-Pointing-Pointer Ab initio density functional theory band structure calculations show that the unusually large second-order optical nonlinearity is attributed to the 2-D character of the crystal structure.

• OSTI ID: 22149900
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Vol. 195; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ABSORPTION SPECTROSCOPY
CHALCOGENIDES
CRYSTAL STRUCTURE
DENSITY FUNCTIONAL METHOD
DIFFERENTIAL THERMAL ANALYSIS
HARMONIC GENERATION
NONLINEAR OPTICS
NONLINEAR PROBLEMS
SEMICONDUCTOR MATERIALS
TWO-DIMENSIONAL CALCULATIONS