Provided is a vertical external cavity surface emitting laser (VECSEL)
including: a bottom DBR mirror formed on a substrate; an RPG layer formed
on the bottom DBR layer; a capping layer formed on the RPG mirror; an
optical pump irradiating a pump beam onto a surface of the capping layer;
and an external cavity mirror installed on an external surface of a
stacked layer corresponding to the bottom DBR mirror. The RPG layer
includes: a plurality of first barrier layers periodically formed on
nodes of a standing wave and formed of a material having a larger energy
band gap width than that of the pump beam; and a plurality of gain layers
including a plurality of QW layers formed of InGaAs and disposed between
the first barrier layers, and a plurality of second barrier layers
disposed on upper and lower portions of the QW layers.