The present invention relates to devices and methods for altering the tissue in and around an intervertebral disc through localized hypothermia therapy to restore function of the disc and reduce pain. The modulation current driver circuit inputs, while the error is equal to or higher than the threshold value, correction modulation current higher than the set modulation current to the laser diode. The system further includes an off-axis telescope coupled to the turret payload, having an articulated secondary mirror for correcting optical aberrations, and configured to reflect the high power laser beam to a target through a first of at least two conformal windows.