This is the magic of the device. We injected pulses of about 1 nanosecond with such a high power green laser pointer, and then they broke down into a very narrow series of short pulses, usually less than 1 picosecond wide. In this way, the equivalent output of an expensive mode-locked laser is obtained with a fiber equivalent to only 20 cents.
Through a process called “supercontinuum generation,” they passed the light beam through a special, softer glass fiber to extend the wavelength range covered by the light. Most lasers emit light of only one wavelength or color, but the focused beam emitted by a supercontinuum laser contains a wider range of wavelengths.
For example, a visible-wavelength supercontinuum laser, because it contains light that penetrates the visible spectral range, the light beam emitted will show white light. The broadband infrared supercontinuum laser developed by the team has the same principle, except for the longer infrared wavelength. When using the device, researchers illuminate a green laser pointer on an object and analyze the reflected light to determine which wavelengths have not been reflected back, and they can identify chemical substances by the characteristic infrared wavelengths they absorb.