"""Doublet compound component for Non-Sequential Raytracing.
A cemented achromatic doublet: front face, cemented interface, back face,
edge (cylindrical frustum).
Kramer Harrison, 2026
"""
from __future__ import annotations
from typing import TYPE_CHECKING
from optiland.nonsequential.components.compound import CompoundComponent
from optiland.nonsequential.components.configs import DoubletConfig, InteractionType
from optiland.nonsequential.components.geometry.analytic.conic import ConicGeometry
from optiland.nonsequential.components.geometry.analytic.frustum import (
CylindricalFrustumGeometry,
)
from optiland.nonsequential.components.lens import (
_make_surface,
_offset_cs,
_resolve_material,
_sag_at_rim,
)
from optiland.nonsequential.components.volume import Volume
from optiland.nonsequential.materials.nsq_material import VACUUM
if TYPE_CHECKING:
from optiland.coordinate_system import CoordinateSystem
from optiland.nonsequential.components.base import BaseComponent
[docs]
class Doublet(CompoundComponent):
"""Cemented achromatic doublet.
Assembles five physical surfaces:
1. **Front face** -- refractive, conic (crown element).
2. **Cemented interface** -- refractive, conic (crown->flint).
3. **Back face** -- refractive, conic (flint element).
4. **Crown edge** -- cylindrical frustum, absorbing.
5. **Flint edge** -- cylindrical frustum, absorbing.
Unlike ``Lens``, a doublet is two closed solids (the crown element and
the flint element) sharing the cemented interface as a common boundary
surface -- so the edge is split into a crown segment and a flint
segment at the cemented interface's axial position, and each element
is validated as its own :class:`Volume`.
Attributes:
_name: Registry name.
_cs: Front-vertex coordinate system.
_config: DoubletConfig.
_surfaces: Built list of sub-surfaces.
_volumes: The two validated ``Volume`` instances (crown, flint).
"""
def __init__(
self,
name: str,
cs: CoordinateSystem,
config: DoubletConfig,
) -> None:
"""Initialize Doublet from a DoubletConfig.
Args:
name: Unique identifier in the registry.
cs: Front-vertex coordinate system.
config: Doublet geometry and material configuration.
Raises:
NonWatertightVolumeError: If either element's surfaces do not
form a closed, consistently outward-oriented solid.
"""
self._name = name
self._cs = cs
self._config = config
mat1 = _resolve_material(config.material1)
mat2 = _resolve_material(config.material2)
self._surfaces: list[BaseComponent] = self._build()
front, cemented, back, edge_crown, edge_flint = self._surfaces
self._volumes = [
Volume(
name=f"{name}.crown",
boundary=[front, cemented, edge_crown],
interior=mat1,
),
Volume(
name=f"{name}.flint",
boundary=[cemented, back, edge_flint],
interior=mat2,
),
]
@property
def name(self) -> str:
"""Registry name."""
return self._name
@property
def surfaces(self) -> list[BaseComponent]:
"""Ordered flat list of sub-surfaces."""
return self._surfaces
@property
def coordinate_system(self) -> CoordinateSystem:
"""Front-vertex coordinate system."""
return self._cs
def _build(self) -> list[BaseComponent]:
"""Construct all four sub-surfaces from the config.
Returns:
Ordered list of BaseComponent sub-surfaces.
"""
cfg = self._config
mat1 = _resolve_material(cfg.material1)
mat2 = _resolve_material(cfg.material2)
r = cfg.aperture_radius
cs_front = self._cs
cs_cemented = _offset_cs(cs_front, cfg.thickness1)
cs_back = _offset_cs(cs_cemented, cfg.thickness2)
surfaces: list[BaseComponent] = []
# 1. Front face (vacuum -> crown)
surfaces.append(
_make_surface(
cs_front,
ConicGeometry(cfg.r1, cfg.conic1, r),
VACUUM,
mat1,
cfg.front,
InteractionType.REFRACTIVE,
f"{self._name}.front",
)
)
# 2. Cemented interface (crown -> flint)
surfaces.append(
_make_surface(
cs_cemented,
ConicGeometry(cfg.r2, cfg.conic2, r),
mat1,
mat2,
cfg.cemented,
InteractionType.REFRACTIVE,
f"{self._name}.cemented",
)
)
# 3. Back face (flint -> vacuum)
surfaces.append(
_make_surface(
cs_back,
ConicGeometry(cfg.r3, cfg.conic3, r),
mat2,
VACUUM,
cfg.back,
InteractionType.REFRACTIVE,
f"{self._name}.back",
)
)
# 4. Crown edge (cylindrical frustum, absorbing) -- front face to
# the cemented interface, so the crown element's own boundary
# closes without the flint element.
sag_front = _sag_at_rim(cfg.r1, cfg.conic1, r)
sag_cemented = _sag_at_rim(cfg.r2, cfg.conic2, r)
sag_back = _sag_at_rim(cfg.r3, cfg.conic3, r)
crown_edge_geom = CylindricalFrustumGeometry(
r_front=r,
r_back=r,
z_front=sag_front,
z_back=cfg.thickness1 + sag_cemented,
)
surfaces.append(
_make_surface(
cs_front,
crown_edge_geom,
VACUUM,
VACUUM,
cfg.edge,
InteractionType.ABSORBING,
f"{self._name}.edge_crown",
)
)
# 5. Flint edge -- cemented interface to back face.
total_thickness = cfg.thickness1 + cfg.thickness2
flint_edge_geom = CylindricalFrustumGeometry(
r_front=r,
r_back=r,
z_front=cfg.thickness1 + sag_cemented,
z_back=total_thickness + sag_back,
)
surfaces.append(
_make_surface(
cs_front,
flint_edge_geom,
VACUUM,
VACUUM,
cfg.edge,
InteractionType.ABSORBING,
f"{self._name}.edge_flint",
)
)
return surfaces
