Novel technologies for small deformable mirrors

Hydroxide catalysis bonding for astronomical instruments

“…Preston et al [18,20] and Preston and Mueller [19] have studied the shear strength of SiC, BK7 and Super Invar with satellite missions like eLISA [48] and SIM [75] in mind. Green et al [21,22] HCB for application in small and large adaptive mirrors for very large telescopes has been studied by Strachan et al [23,24], particularly for bonding PZT (lead zirconate titanate) actuators to silicon and SiC mirror substrates. Sodium silicate solution was used to bond PZT substrates to silicon substrates and shear strengths were evaluated.…”

“…Materials reported in the literature as substrate material for bonding are fused silica [7-9, 13, 28, 32-37], Zerodur ® [13,21], ULE ® [21,22], SiC [15][16][17][18][19][20], silicon [32,[38][39][40][41], sapphire [25,34,40,42], BK7 [18,26], glass and aluminium [26], soda lime glass [27] and PZT [23,24]. Examples of hydroxide solutions commonly used for bonding are potassium hydroxide (KOH) [9,13,21,25,33,36,40,41], sodium hydroxide (NaOH) [13,21,22,25] and sodium silicate solution [13, 16-21, 23-26, 28, 32, 34-39], which is a sodium hydroxide solution with a colloidal silicate (typically 10-14% NaOH, 27% SiO 2 ) dissolved in water.…”

“…It was originally developed and patented for the Gravity Probe B space mission to assemble the fused silica star tracking telescope at Stanford University [7][8][9] and has since found its application in adapted form in gravitational wave (GW) detectors (both groundbased [10][11][12] and space-based [13,14]) as well as being considered for other applications in the field of astronomy [15][16][17][18][19][20][21][22][23][24] and beyond [25][26][27][28][29].…”