Second-harmonic scanning optical microscopy of poled silica waveguides

Abstract

Second-harmonic scanning optical microscopy ͑SHSOM͒ is performed on electric-field poled silica-based waveguides. Two operation modes of SHSOM are considered. Oblique transmission reflection and normal reflection modes are used to image the spatial distribution of nonlinear susceptibilities in the sample surface plane and in depth. It is shown that the spatial resolution in normal reflection mode can be better than 1 m for second-harmonic images. A simple qualitative description of this operation mode is suggested and found to be in good agreement with the results obtained. Advantages and limitations of the two operation modes when used for SHSOM studies of poled silica-based waveguides are discussed. The influence of surface defects on the resulting second-harmonic images is also considered.

Second‐harmonic far‐field microscopy of random nanostructured gold surfaces

“…Second harmonic scanning optical microscopy (SHSOM), which uses spatially resolved detection of SH radiation opened up an alternative and novel technique for local probing of enhanced SH generation at rough metal surfaces. SHSOM has been successfully used for imaging of periodically poled ferroelectric domains [7,8], domains in polycristalline metals [9], poled silica waveguides [10], semiconductor quantum dots [11], and individual microstructures [12]. Using a SHSOM, here we report the direct observations of strong and spatially localized SH enhancement in random metal nanostructures.…”

Advances in silica-based integrated optics

“…40 After poling, the samples were cleaved through the poled area and the distribution of the first-order nonlinearity (2) along the coordinate parallel to the poling field was investigated. 58,59 One of the recorded images is shown in Fig. 13.…”

“…58,59 One of the advantages of using waveguides compared to bulk samples or fibers is that it is possible to test the influence of many parameters, such as waveguide width, poling voltage, poling temperature, and poling time on sections of the same sample. In addition to the direct electro-optic measurements in the interferometer, we have measured (2) and (3) using poled gratings.…”

“…In the optical regime, SHG is used in reflection mode to study the spatial distribution of the nonlinear properties with micron resolution. 58,59 Also, secondary ion mass spectrometry ͑SIMS͒ is used to study chemical changes with submicron depth resolution. 40 The latest experimental result obtained with negative poling shows an electro-optic coefficient of rϭ(0.093 Ϯ0.001) pm/V corresponding to (2) Ϸ(0.230 Ϯ0.002) pm/V.…”

Electric‐field‐induced second‐harmonic microscopy

“…This electric field-induced second-harmonic (EFISH) process, first demonstrated in the 1960s [1], has been widely employed as a probe of electric fields in semiconductor devices [2,3,4,5,6,7] and in aqueous environments [8,9,10]. However, despite extensive development of second-harmonic microscopy in other contexts [11,12,13], the potential of EFISH for diffraction-limited microscopy of electric fields remains largely untapped [14]. In this paper, we demonstrate EFISH microscopy of electric fields at metal-silicon junctions.…”