A spectro-sensor comprising: a nano antenna array comprising a first nano antenna and at least a second nano antenna that have different respective resonance wavelength bands; and an optical detector array comprising a first optical detector and at least a second optical detector that respectively detect light from the first nano antenna and the second nano antenna; characterised in that each of the first nano antenna and the at least the second nano antenna comprises: a respective upper nano-structure layer that has a first stacked structure in which a first dielectric layer that has a first refractive index and a second dielectric layer that has a second refractive index that is higher than the first refractive index are alternately stacked along a first direction, and a respective first plurality of nano holes formed to pass through the first stacked structure; a respective lower nano-structure layer which has a second stacked structure in which a third dielectric layer that has a third refractive index and a fourth dielectric layer that has a fourth refractive index that is higher than the third refractive index are alternately stacked along the first direction, and a respective second plurality of nano holes formed to pass through the second stacked structure; and a respective intermediate layer of dielectric material disposed between the corresponding upper nano-structure layer and the corresponding lower nano-structure layer. a nano antenna array comprising a first nano antenna and at least a second nano antenna that have different respective resonance wavelength bands; and an optical detector array comprising a first optical detector and at least a second optical detector that respectively detect light from the first nano antenna and the second nano antenna; characterised in that each of the first nano antenna and the at least the second nano antenna comprises: a respective upper nano-structure layer that has a first stacked structure in which a first dielectric layer that has a first refractive index and a second dielectric layer that has a second refractive index that is higher than the first refractive index are alternately stacked along a first direction, and a respective first plurality of nano holes formed to pass through the first stacked structure; a respective lower nano-structure layer which has a second stacked structure in which a third dielectric layer that has a third refractive index and a fourth dielectric layer that has a fourth refractive index that is higher than the third refractive index are alternately stacked along the first direction, and a respective second plurality of nano holes formed to pass through the second stacked structure; and a respective intermediate layer of dielectric material disposed between the corresponding upper nano-structure layer and the corresponding lower nano-structure layer. a respective upper nano-structure layer that has a first stacked structure in which a first dielectric layer that has a first refractive index and a second dielectric layer that has a second refractive index that is higher than the first refractive index are alternately stacked along a first direction, and a respective first plurality of nano holes formed to pass through the first stacked structure; a respective lower nano-structure layer which has a second stacked structure in which a third dielectric layer that has a third refractive index and a fourth dielectric layer that has a fourth refractive index that is higher than the third refractive index are alternately stacked along the first direction, and a respective second plurality of nano holes formed to pass through the second stacked structure; and a respective intermediate layer of dielectric material disposed between the corresponding upper nano-structure layer and the corresponding lower nano-structure layer.