This invention proposes to use a specially designed layered nonlinear optic (LNO) for intracavity harmonic generation. The LNO generates the harmonic and guides the generated harmonic beam to a different path from the fundamental beam path with total internal reflection, a phenomenon that all lights are reflected when lights in one (“internal”) optic strike sufficiently obliquely against the interface with a second (“external”) optic, in which the refractive index is lower than that in the internal optic. No coating is necessary for the harmonic inside the fundamental beam laser cavity. The generated harmonic beam does not travel through any surface inside the fundamental beam cavity, either. Hence this invention improves the reliability of intracavity harmonic generation laser especially if the harmonic is in the UV range.