# User:Pranav Rathi/Notebook/OT/2010/12/10/Olympus Water Immersion Specs

### From OpenWetWare

## Water immersion objective details

WE are using Olympus UPLANSAPO (UIS 2) water immersion IR objective for DNA stretching and unzipping. The detail specifications of the objective can be found in the link:[1] Other specification are as follows;

Mag | 60X |

Wavelength | 1064 |

NA | 1.2 |

medium | water |

Max ray angle | 64.5degrees |

f # | 26.5 |

Effective FL in water | 1.5 to 1.6mm (distance between the focal spot and the exit aperture surface) |

Entrance aperture diameter | 8.5mm |

Exit aperture diameter | 6.6mm |

Working distance | .28mm |

Cover glass correction | .13 to .21 (we use .15) |

### Resolution and achievable spot size

The resolution and the spotsize (beam waist) presented here is in the theoretical limits; we cannot achieve better than this. Resolution and spotsize are diffraction limited and to reach these limits our optics has to be perfect; no aberrations and other artifacts. Since our optics is not perfect and very clean we can hardly reach these limits in real life; definitely the resolution and spotsize in real is worse than the numbers presented here. A good way to do a quick estimation of the resolution (diameter of the airy disk) is that its 1/3 of a wavelength λ=.580 μm; λ/3*n= 145 nm. Since we do all our experiments in water we will have take index of water in account (n=1.33). I am ignoring the NA of the condenser in the calculations.

- Wavelength of the visible light λ
_{v}= .590μm. - Wavelength of the IR λ
_{IR}= 1.064μm. - Diameter of the incident beam at the exit pupil (D=2ω'
_{o}.)=6500μm. (ω'_{o}is the incident beam waist) - Focal length of the objective f=1500μm.
- Angular resolution inside water:

- Spatial resolution in water;

Since we are not too sure of the focal length of the objective, so i derived the resolution formula in terms of the numerical aperture NA.

- Resolution in terms of NA:

**Failed to parse (syntax error): \mathrm{\Delta l} = \frac{1.22\lambda_v}{2n}\sqrt{\frac{{n}{NA}}^{2}-1}= 122nm**