Dual-trap technique for reduction of low-frequency noise in force measuring optical tweezers.
High-resolution long-time force measurements by optical tweezers are often limited by low-frequency (1/f) noise. A dual-trap technique is presented that can reduce such noise in the force signal. It incorporates a second trap (a reference trap) that probes the noise in the system and it is based upon the assumption that the low-frequency parts of the noise from the two traps are correlated. A subtraction of the low-frequency signal from the reference trap from the signal from the force measuring trap will therefore yield a net signal that is significantly less influenced by noise. It is shown that this dual-trap technique can reduce the noise in the force signal up to 60% depending on detection bandwidth.
Klein
Markus
M
Department of Physics, Umeå University, Sweden.
Andersson
Magnus
M
Axner
Ove
O
Fällman
Erik
E
D004867:Equipment Design; D007834:Lasers; D008846:Micromanipulation / Q000295:instrumentation* / Q000379:methods*; D015233:Models, Statistical; D008962:Models, Theoretical; D009038:Motion; D055095:Optics and Photonics; D010316:Particle Size; D013997:Time Factors