Publications by authors named "Mandira Pal"

In this paper, we study parametric optical rectification that is not due to material properties but emerges from the electrostatic near-field interaction between nanosized metallic domains. The ability to demonstrate this effect comes from samples based on a unique slab waveguide with deeply buried nanometer-thin metallic layers. These samples intensify the presumed rectification mechanism while suppressing competing effects.

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We experimentally study the optical second-harmonic generation (SHG) from deep subwavelength gold-silver heterodimers, and silver-silver and gold-gold homodimers. Our results indicate a heterodimer SHG that is an order of magnitude more intense than that of the homodimers. In contrast, full-wave calculations that consider the surface and bulk contribution of individual particles, which is the conventional view on such processes, suggest that it is the silver-silver homodimer that should prevail.

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The extraordinary concept of weak value amplification can be formulated within the realm of wave interference as nearly destructive interference between the eigenstates of the measuring observable. Here we report on a phenomenon of interferometric weak value amplification of small polarization rotation in Fano resonance that evolves completely naturally due to near destructive spectral domain interference between a continuum and a narrow resonance mode having slightly different polarization response. In order to elucidate this, we first experimentally demonstrate an interferometric weak value amplification concept by generating nearly destructive interference of two paths of an interferometer having slightly rotated linear polarization states of light.

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Spin orbit interaction and the resulting Spin Hall effect of light are under recent intensive investigations because of their fundamental nature and potential applications. Here, we report an interesting manifestation of spin Hall effect of light and demonstrate its tunability in an inhomogeneous anisotropic medium exhibiting spatially varying retardance level. In our system, the beam shift occurs only for one circular polarization mode keeping the other orthogonal mode unaffected, which is shown to arise due to the combined spatial gradients of the geometric phase and the dynamical phase of light.

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