Mode Matching - second try

Mirror configuration

Parameter

Radius of curvature of mirror R1: R1= 1 m

Radius of curvature of mirror R2: R2= 1 m (Incoupling side)

Wavelength: λ= 1542.0 nm

Length between the resonator mirrors: L= 480 mm

Beam radius at cavity-waist: w0

Beam radius at mirror: w1, w2

Distance between:

mirror R1 and mirror R2: L

mirror R2/lense 1 and lense 2: X

mirror R2/lense 1 and collimatorlense: 600mm - X

600mm (+15mm) = optical way of the incoupling breadboard (450mm) + thickness breadboard (10mm) + distance between breadboard and vacuumchamber (30mm) + distance between vacuumchamber and cavity mirror R2 (130mm)

collimatorlense and fiber: 2.75 mm

We used the programm Strahl.exe (@IQ) or STRAHLFP.EXE (@PTB) (same software, but different names).
Step 0: Choose parameter

Wellenlänge: 1542 nm

Brechungsindex: 1

Welcher Resonatortyp: linearer Resonator

Step 1: Beam waist calculation from resonator

Nr. 1: Spiegel 1 with R1 = 1 m; Einfallwinkel: 0

Nr. 2: Abstand 480 mm

Nr. 3: Spiegel 2 with R2 = 1 m; Einfallwinkel: 0

→ Waistradius: 457 µm; Strahlradius on the mirrors: 525.2 µm

Step 2:

Change Spiegel 2 to Linse 1

Brechungsindex: 1.5

Brennweite: -2000 mm

The values of the Waistradius and Strahlradius must not change!!!

Step 3:

Nr. 4: Abstand with Variable X

Nr. 5: Linse 2 with Variable Y

Nr. 6: Abstand 600 - X

Nr. 7: Linse 3 with Brennweite 2.75 mm

Nr. 8: Abstand 2.75 mm

Step 4: Playing with the parameters X and Y for the best Überlapp