noise investigation for optical tweezers
DESCRIPTION
This presentation is dedicated to the noise problems faced in optical tweezers.TRANSCRIPT
1
Noise Investigation for Optical Tweezers
2
60Hz noise Investigation-next 5
slides
3
60 Hz noise identification60Hz
#6
Data taken on may/18/2011
44
Identification cont…
#660Hz
Data taken on june/02/2011
5
Source identification and Solution• First source : AC power cables running close to the QPD signal wires• Second source: Power supply of on track was not grounded
Solution
• All the signal wires were rearranged and separated from AC wires• On track was powered by Ryobi lithium-battery
6
Results
Data taken on june/30/2011
No 60 Hz noise
7
Results No 60 Hz noise
Data taken on July/14/2011
8
120Hz Investigation Onwards
9
Noisy DOG Vs ideal DOG
10
Ideal Data Vs Noisy Data
11
Test for resonant frequency of the setup- next 17 slides
Sample plane
Tweezers structure
Tone generator
12
13
Test-Results frequency Vs DOG-profileAt 0 Hz
#12
At 100 Hz #10
At 105 Hz #10
14
Cont….
At 110 Hz#11
At 115 Hz
#11.5
At 120 Hz
#12
Resonance HIT
15
Cont….At 125 Hz
#12.5
At 130 Hz#13
At 135 Hz
#13.5
16
Cont….
At 150 Hz
At 140 Hz
At 145 Hz
#14
#14
#15
17
Cont….At 160 Hz
At 170 Hz
At 180 Hz
#16
#17
#18
Another hit
18
Cont….At 200 Hz
At 225 Hz
At 300 Hz
#20
#24
#30
Another hit
19
Cont….At 350Hz
At 400 Hz
At 450Hz
Beating
Beating
Beating
20
Cont….At 500Hz
At 550Hz
At 600Hz
Beating
Beating
Beating
21
Cont….At 650Hz
At 700Hz
At 750Hz
Beating
Beating
Beating
22
Cont….At 800Hz
At 850Hz
At 900Hz
Beating
Beating
Beating
23
Cont….At 950Hz
At 1000Hz
At 1100Hz
Beating
Beating
Beating
24
Last one..
At 2000Hz
Beating
25
Power spectrum comparisonspeaker on optical table Vs chairOT chair
0Hz
26
Cont….
cc
OT chair
120Hz
27
Cont…
cc
At 180 Hz
OTChair
28
Cont….chairOT
300Hz
29
Cont….lastone
chairOT
600Hz
Noise detection in the data
30
31
Data Analysis
32
33
34
35
36
•Vibration transmissivity wise structure is most sensitive to 100 to 150Hz and more sensitive to the frequencies less than 400Hz.
•Power coupling from frequencies higher than 150Hz wise 295Hz is the strongest candidate.
•Airborne noise wise structure is most sensitive to frequencies less than 140Hz.
•120 Hz is the mechanical resonant frequency of the structure.
•180Hz and 295Hz are the secondary resonance.
Summary