 <unk> – cadmium lasers are a common source of blue @-@ ultraviolet laser light . They operate at either 325 or 422 nm in fluorescence <unk> and various laboratory experiments . Cadmium selenide quantum dots emit bright luminescence under <unk> <unk> ( He @-@ Cd laser , for example ) . The color of this luminescence can be green , yellow or red depending on the particle size . <unk> solutions of those particles are used for imaging of biological tissues and solutions with a fluorescence microscope . 
