Measuring and testing – Surface and cutting edge testing – Roughness
Reexamination Certificate
2001-09-27
2004-12-28
Williams, Hezron (Department: 2856)
Measuring and testing
Surface and cutting edge testing
Roughness
C324S244100, C250S306000, C250S307000
Reexamination Certificate
active
06834537
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an optical microcantilever capable of effectively propagating light, and a manufacturing method thereof, and a microcantilever holder for fixing an optical element actuated by the optical microcantilever and light incident to the optical microcantilever, and light outputted from the optical microcantilever.
BACKGROUND ART
With such scanning near field microscopes, the tip of a rectilinear optical fiber probe maintained perpendicular to the sample is made to vibrate horizontally with respect to the sample surface and changes in the amplitude of vibrations occurring due to the shear force between the sample surface and the tip of the optical fiber are detected. Changes in the amplitude are detected by irradiating the tip of the optical fiber probe with laser light and detecting changes in the shadow of the tip. A gap between the tip of the optical fiber probe and the surface of the material is kept fixed by moving the sample using a fine-motion mechanism so that the amplitude of the vibrations of the optical fiber probe are constant, and the shape of the surface is detected and the optical permeability of the sample measured from the intensity of a signal inputted to the fine-motion mechanism.
There is also proposed (in Japanese Patent Publication Laid-open No. Hei. 7-17452) a scanning near field atomic force microscope where near field light is generated at the tip of an optical fiber probe as a result of introducing laser light into an optical fiber probe simultaneously with an AFM operation employing the pointed optical fiber probe as a cantilever for an atomic force microscope (hereinafter referred to as AFM) and the shape of the surface of a sample is detected and the optical characteristics of the sample are measured using the mutual interaction between the generated near field light and the sample.
FIG. 12
is a side cross-section of a related example of an optical waveguide probe. This optical waveguide probe
110
employs an optical waveguide
101
as an optical fiber and the optical waveguide
101
is surrounded by a metal film
102
. A pointed tip
103
is formed at one end of the optical waveguide probe
110
and a microscopic aperture
104
for generating near field light is provided at the end of the tip
103
. The tip
103
is formed by bending the tip of the optical waveguide probe
110
around towards the sample (not shown).
Microcantilevers of the kind shown in
FIG. 13
are well known in the related art (T. Niwa et al., Journal of Microscopy, vol. 194, pt. 2/3, pp. 388-392). At an optical microcantilever
120
, an optical waveguide
11
I is laminated from a core layer and a cladding layer and a metal film
112
is provided at the surface of the optical waveguide
111
. A pointed tip
119
is formed at one end of the optical microcantilever
120
and a support section
114
for fixing the optical microcantilever
120
is formed at the other end of the optical microcantilever
120
. A microscopic aperture
113
for generating near field light is provided at the end of the tip
119
.
The end of the optical microcantilever
120
at which the tip
119
is formed is referred to as the free end of the cantilever, and the optical waveguide end where the support section
114
is formed is referred to as the incident light end
117
. The free end is bent in such a manner that the microscopic aperture
113
becomes in close proximity to the sample (not shown), and light propagated from the incident light end
117
enters the optical waveguide
111
.
An optical fiber guide channel
115
for fixing the optical fiber is formed at the support section
114
.
FIG. 14
shows the situation when an optical fiber
130
is fixed to the optical fiber guide channel
115
. Light propagating from the optical fiber
130
enters the optical waveguide
111
via the incident light end
117
and is guided to the microscopic aperture
113
by the optical waveguide
111
. Near field light is generated in the vicinity of the microscopic aperture
113
as a result of propagating light attempting to pass through the microscopic aperture
113
. Conversely, near field light generated at the surface of the sample is scattered by the microscopic aperture
113
so as to generate propagating light and this propagating light can be detected at the incident light end
117
via the microscopic aperture
113
and the optical waveguide
111
. Installation of the optical fiber
130
is straightforward because the optical fiber guide channel
115
is provided at the support section
114
and there is little trouble involved in aligning the optical microcantilever
120
and the optical fiber
130
during changing, etc.
However, productivity for the optical waveguide probe
110
is poor because the optical fiber
101
is employed as a material, which involves a large number of steps and is made manually. Further, even if the optical fiber
101
is covered in the metal film
102
, propagating light loss occurs at locations where the optical fiber
101
is bent and light is therefore not propagated in an efficient manner, with this loss becoming more substantial as the angle of bending becomes more dramatic. Conversely, if the angle of bending is made smoother, the optical fiber probe becomes longer and handling therefore becomes more troublesome.
The optical microcantilever
120
has superior productivity and uniformity but loss of propagating light occurs at the optical waveguide
111
even when the metal film
112
is provided at the surface of the optical waveguide
111
and the propagating light cannot be propagated in an effective manner. In this manufacturing process, a smooth sloping surface
116
occurs between the incident light end
117
and the optical fiber guide channel
115
as shown in FIG.
14
and it is therefore difficult to get the optical fiber
130
sufficiently close to the incident light end
117
and the efficiency of the incident light is poor, i.e. coupling loss increases. Light is scattered at the incident light end
117
of the optical microcantilever
120
while light is made to pass through the incident light end
117
by the optical fiber
130
and scattered light also propagates in the direction of the microscopic aperture
113
. This therefore causes the S/N ratio of a light image for the scanning type near field microscope to fall.
In order to resolve the aforementioned problems in the conventional art, it is an object of the present invention to provide an optical microcantilever bar capable of admitting and propagating light in an efficient manner, and a manufacturing method for making the optical microcantilever. It is a further object to provide an optical microcantilever holder for supporting the optical microcantilever bar and an optical element. It is a still further object to provide an optical microcantilever bar capable of improving an S/N ratio of a light image of a scanning near field microscope.
SUMMARY OF THE INVENTION
In order to achieve the aforementioned objects, an optical microcantilever according to a first embodiment of the invention is an optical microcantilever for use with a scanning near field microscope and comprises an optical waveguide, having a light input/output end and a free end, for propagating light, a tip formed at the free end, with a microscopic aperture at an end thereof, and reflecting means for reflecting light propagated from the light input/output end in such a manner that the light is guided towards the microscopic aperture, or reflecting light propagated from the microscopic aperture towards the light input/output end.
The above optical microcantilever is provided with reflecting means for reflecting light propagated from the light input/output end in such a manner that the light is guided towards the microscopic aperture, or reflecting light propagated from the microscopic aperture towards the light input/output end. This reflecting means reflects propagating light in an efficient manner and reduces loss in light propagated towards the microscopic aperture.
Further, an optical micro
Chiba Norio
Ichihara Susumu
Kasama Nobuyuki
Kato Kenji
Mitsuoka Yasuyuki
Adams & Wilks
Jackson André K.
Seiko Instruments Inc.
Williams Hezron
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