A flashlamp device having a small diameter waveguide is disclosed for use in localized dermatological applications. A preferred waveguide has a curvilinear wall surface. The waveguide is supported by a plurality of spaced apart thermally-conductive elements in contact with the curvilinear wall surface allowing sufficient cooling of the waveguide while minimizing the amount of high angle light stripped from the waveguide at points of contact with the contact elements.