Multi-wavelength optical apparatus includes an optical emitter, and an energy transition layer positioned adjacent to the optical emitter. The energy transition layer generates multi-wavelength electromagnetic radiation when monochromatic light from the optical emitter passes therethrough. The energy transition layer includes a plurality of luminescent films, and each film is configured to luminesce at a respective different wavelength range when monochromatic light from the optical emitter passes therethrough. The plurality of luminescent films may be arranged in contacting face-to-face relationship or may be arranged in an array. The luminescent films may include rare-earth doped oxides, phosphors, metal-doped oxides, rare-earth doped nitrides, nanostructures, and/or nanostructured films, etc. The optical emitter may be a light emitting diode (LED), a laser diode (LD), an organic light-emitting diode (OLED), a resonant cavity light emitting diode (RCLED), and/or an edge-emitting diode (EELED).
