Why we did not use normal glass (silica glass)in the surface plasmon resonance(SPR) based sensor ??

I have designed a SPR chip by using normal glass slide(Blue star No. 4slide)/Cu(5nm)/Ag(50nm). But it shows very less depth in the reflectance curve at resonance angle. What should be the reason ??

14 February 2020 3,902 4 View