  We propose and experimentally demonstrate femtosecond direct laser writing
with Bessel beams for the fabrication of photonic crystals with spatial
filtering functionality. Such filters are mechanically stable, of small (of
order of millimeter) size, do not require direct access to the far-field
domain, and therefore are excellent candidates for intracavity spatial
filtering applications in mini- and micro-lasers. The technique allows the
fabrication of efficient photonic crystal spatial filters in glass, with a
narrow angle (~1 degree) nearly 100%-transmission pass-band between broad angle
(up to 10 degrees) nearly 0%-transmission angular stop-bands. We show, that
this technique can not only significantly shorten the fabrication time, but
also allows the fabrication of large-scale defect-free photonic crystal spatial
filters with a wide filtering band.
