Abstract: Methods, systems, and devices related to downhole wellbore operations such as drilling and completing wells in an earth formation that include a laser device. The method includes lasing a rock and detecting an optical response of the lased rock. It can be determined from the optical response whether the lased rock is responding as specified (e.g. spalling, melting, etc.) If the lased rock is not responding as specified, one or more laser parameters are adjusted to achieve the specified response. Spalling is determined by the detection of sparks, or other light that erratically changes in intensity over time, by an optical detector. The detection of steady light may indicate other types of rock removal mechanisms, such as melt or dissociation.

Abstract: A lighting system include a point light source, a tubular color adjustment means, and a light-collecting and mixing element. The color adjustment means has a color-converting tubular structure and an adjusting rod. The tubular structure is made of a light-transmitting medium doped with a wavelength-converting material. The adjusting rod is operably connected to and for adjusting the tubular structure. In operation, the point light source emits light of a first wavelength or hue. The color adjustment means adjustably intersects, through the use of the adjusting rod, the light of the first hue and converts at least a portion of the light of a first hue into a light of another hue. The light-collecting and mixing element collects and mixes the light of a first hue and the light of another hue, and directs the mixed light out the open end.