Sub-Wavelength THz Imaging of the Domains in Periodically Poled Crystals Through Optical Rectification

• By focusing a femtosecond laser beam onto the lateral face of a periodically poled KTP crystal, we generate a THz pulse through optical rectification of the laser pulse. The THz signal is recorded by means of a common THz time-domain technique, which allows us to obtain both the magnitude and sign of the THz waveform, and then the magnitude and phase of its spectral components thanks to a numerical Fourier-transform. By moving the laser beam along the crystal, we record a THz signal that renders for the alternative orientation of the crystal domains, with a lateral resolution as good as 10 mu m, whatever the THz wavelength. This demonstrates the potential of the Optical Rectification TeraHertz Imaging (ORTI) technique to produce sub-wavelength THz images.

Ämnesord

NATURVETENSKAP  -- Fysik -- Atom- och molekylfysik och optik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Atom and Molecular Physics and Optics (hsv//eng)

Nyckelord

Optical rectification

Periodically poled crystals

THz microscopy

THz time-domain spectroscopy

Crystal orientation

Crystals

Laser beams

Crystal domain

Lateral resolution

Optical rectifications

Periodically poled KTP

Spectral components

Terahertz imaging

Time-domain technique

Time domain analysis

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