A VCSEL includes a grating layer configured with a non-periodic, sub-wavelength grating, in which the non-periodic, sub-wavelength grating includes at least one first section configured to have a relatively low reflection coefficient and at least one second section configured to have a relatively high reflection coefficient to cause light to be reflected in a predetermined, non-Gaussian, spatial mode across the sub-wavelength grating. The VCSEL also includes a reflective layer and a light emitting layer disposed between the grating layer and the reflector, in which the sub-wavelength grating and the reflector form a resonant cavity.