Nonlinear optical generation using electromagnetically induced transparency in atomic hydrogen

Nonlinear optical generation using electromagnetically induced transparency is demonstrated with atomic hydrogen as a test medium. With the application of a strong-coupling laser field to the 3p-2s transition, the resonant Lyman-{β} (3p-1s) transition becomes transparent. The generated-sum-frequency Lyman-{β} radiation at 103 nm can continue to grow without suffering resonant absorption and phase mismatching.