Variable reflectivity notch filter and optical devices using same

A variable reflectivity notch filter (100), suitable for use with a laser image projection source (1001) is provided. The variable reflectivity notch filter (100) defines a transmission curve (101) having a plurality of reflective peaks (102,103,104) each centered about a predetermined wavelength (105,106,107), which can correspond to output wavelengths from laser sources. Reflective peaks (204) corresponding to wavelengths that change with temperature are configured with wider widths (223) and lesser reflectivities (210) than are other reflective peaks (202,203). To provide enhanced color balance, lasers (821) corresponding to these reflective peaks (204) can be driven at higher output power. Variable reflectivity notch filters (100) are suitable for use in head-up displays as well as other applications.