title: Tailoring and tuning of the broadband spectrum of a step-chirped grating based frequency doubler using tightly-focused Gaussian beams.
abstract: We demonstrate theoretically and experimentally, that the non-uniform spectra of second harmonic generation (SHG) from an unapodized step-chirped periodically poled nonlinear optical grating can be apodized utilizing tightly-focused Gaussian beams to suppress the ripple in its wideband response. In our example, by increasing focusing, a ripple-free response is progressively achieved over a 6-dB bandwidth of >5 nm, with a beam waist of 20 µm. With this tight focusing arrangement, a continuous tuning of 11-nm is also demonstrated by simply changing the focal point by 5.8 mm within the step-chirped grating based APPLN.
authors: Ameneh
authors: A
authors: Bostani
authors: Meenu
authors: M
authors: Ahlawat
authors: Amirhossein
authors: A
authors: Tehranchi
authors: Roberto
authors: R
authors: Morandotti
authors: Raman
authors: R
authors: Kashyap