Articolele autorului Silviu Popescu
Link la profilul stiintific al lui Silviu Popescu

Recording of self-induced waveguides in lithium niobate at 405 nm wavelength by photorefractive – pyroelectric effect

We characterize the process of soliton waveguides (SWGs) recording at 405 nm wavelength using pyroelectric effect in lithium niobate (LN) crystals. We experimentally study and discuss the influence of the input irradiance, the polarization of the signal beam, and the crystal temperature change on the waveguide writing time and mode-profile. These characteristics significantly change when changing the recording wavelength. The advantages of recording

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Fast writing of soliton waveguides in lithium niobate using low-intensity blue light

We experimentally demonstrate the writing of soliton waveguides in lithium niobate with blue violet light, at λ = 405 nm. This wavelength, obtained from a low-cost laser diode, allows very fast writing of soliton waveguides when comparing with the writing process using green light (532 nm). For the same writing time, there is a decrease of ~4 orders of magnitude of the light intensity necessary for writing soliton waveguides in blue. The writing

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Interferometric measurement of the pyroelectric coefficient in lithium niobate

We report the measurement of pyroelectric field in LiNbO3 by introducing a new method, based on optical interferometry. The pyroelectric coefficient of the congruent LiNbO3 crystals has been determined by this method and the value obtained for it, similar to 95 mu C/(m(2).K), is consistent with previous results reported in literature, obtained by other methods.

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Use of quasi-local photorefractive response to generated superficial self-written waveguides in lithium niobate

We report the formation of surface self-written waveguides by means of surface pyrolitons in lithium niobate. By a specific orientation of the crystal axis the quasi-local slow photorefractive response of lithium niobate was used to induce a self-confined beam exactly at the crystal-air interface. The mode profile of the photo-induced waveguide is strongly asymmetric due to the interface presence.

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